WI - Cormorant Research Group Scientific Literature - Double-crested cormorant updated on 13-08-2010

Scientific literature on the
Double-crested Cormorant - Phalacrocorax auritus

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Enstipp M.R., Grémillet D. & Jones D.R. 2007. Investigating the functional link between prey abundance and seabird predatory performance. MEPS, 331: 267-279. [Abstract. Investigating the relationships that link marine top predators and their prey is crucial for an understanding of the mechanisms that operate within marine food chains. Many seabird species capture their prey underwater, where direct and continuous observation is difficult. However, in a captive setting, predator–prey interactions can be studied under controlled conditions and in great detail. Using an underwater video-array, we investigated the prey–capture behaviour of a foot-propelled pursuit diver, the double-crested cormorant Phalacrocorax auritus, targeting juvenile rainbow trout Oncorhynchus mykiss. We tested the effects of prey density, prey size, light conditions and prey behaviour (schooling vs. solitary trout) on the foraging performance of 9 cormorants. As predicted, prey density exerted the strongest influence on cormorant foraging success. While we found an apparently linear relationship between prey density and prey capture rate, a density below the threshold of about 2 g m resulted in disproportionately lower catch per unit effort (CPUE) values. If such a threshold density exists in a natural setting, it could have important implications for birds confronted with a decline in food abundance, when density levels will be reduced. We also demonstrate the marked impact of fish behaviour on the predatory performance of cormorants. Capture success of cormorants was significantly lower and pursuit duration significantly higher when birds attacked schooling rather than solitary trout. By contrast, prey size and light conditions did not have a measurable effect on cormorant prey–capture performance. Our study is an experimental investigation into the prey–capture performance of an avian pursuit diver within a captive setting. We provide input values that should be incorporated into ecological models, which might help to understand predator requirements in a changing environment.]

Lyons DE, DD Roby, and K Collis. 2007. Foraging patterns of Caspian terns and double-crested cormorants in the Columbia River estuary. Northwest Science 81:91-103.




Anderson CD., DD Roby, and K Collis. 2004. Conservation implications of the large colony of double-crested cormorants on East Sand Island, Columbia River estuary, Oregon, USA. Waterbirds 27:155-160.

Anderson CD, DD Roby & K Collis. 2004. Foraging patterns of male and female double-crested cormorants nesting in the Columbia River estuary. Canadian Journal of Zoology 82:541-554.

Dorr B., King D.T., Tobin M.E., Harrel J.B. & Smith P.L. 2004. Double-crested cormorant movements in relation to aquaculture in Eastern Mississippi and Western Alabama. Waterbirds 27(2): 147-154. [Abstract. Concomitant with increasing numbers of the Double-crested Cormorant (Phalacrocorax auritus), catfish producers in eastern Mississippi and western Alabama have reported damage caused by cormorant predation. VHF telemetry was used to document movements of 25 cormorants from all known night roosts in the aquaculture producing areas of eastern Mississippi and western Alabama, January-April 1998. A total of 193 day locations and 396 night roost locations of the cormorants were obtained. Each cormorant was found in the study area for 57 (+/-4) (SE) days. Each cormorant averaged three night roosts (range: 1-8) and spent 20 (+/-2) days at each night roost site. Over 95% of cormorant day locations were within 19 km of their night roosts. Catfish pond use by cormorants varied between roost sites. Cormorants from five of eleven night roosts had 30% of subsequent daytime locations on catfish ponds and birds from five of the six remaining night roosts did not visit catfish ponds on the following day. Foraging distance and frequency of night roost interchange was less for birds in this study than those reported from other aquaculture regions. We suggest roost harassment efforts should be focused on specific roost sites and some roost sites should serve as unharrassed refugia from which cormorants are less likely to cause damage to aquaculture.]


Hilscherova K., Blankenship A., Kannan K., Nie M., Williams L.L., Coady K., Upham B.L., Trosko J.E., Bursian S. & Giesy J.P. 2003. Oxidative stress in laboratory-incubated double-crested cormorant eggs collected from the Great Lakes. Arch Environ Contam Toxicol., 45(4): 533-46. [Abstract. Double-crested cormorant (Phalacrocorax auritus) eggs were collected in 1998 from three sites on Lakes Huron and Superior and either analyzed for 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-like residues or artifically incubated. Some of the incubated eggs were injected with vitamin E (antioxidant) or piperonyl butoxide (CYPIA blocker) to examine the role of CYPIA and oxidative stress in normal bird development. Embryos (day 23) were analyzed for hepatic ethoxyresorufin O-deethylase (EROD) activity and different measures of oxidative stress. Glutathione-related parameters were also measured in brain. In contrast to the historical data, there were no statistically significant differences in concentrations of chlorinated dioxins, furans, dioxin-like PCBs, or total TCDD-equivalents (TEQs) in eggs among sites. Survival and incidence of abnormalities were comparable at all study sites. Slight differences in liver, heart, and egg weight were observed among sites. A greater incidence of eye deformities was observed in embryos treated with vitamin E. Treatment with the CYPIA blocker, piperonyl butoxide, decreased the body weights of embryos. EROD activities were similar at all locations, but measures of oxidative stress varied among locations. There were greater levels of oxidized glutathione and oxidative DNA damage at Little Charity Island in Saginaw Bay. There was relatively great interindividual variation in biochemical responses and significant interrelation of the parameters of oxidative stress. While exposure to PCDD/DF and PCBs does not seem to explain the observed oxidative stress, the potential of these compounds to cause the observed effects can not be completely excluded.]

Weingartl H. M., Riva J. & Kumthekar P. 2003. Molecular Characterization of Avian Paramyxovirus 1 Isolates Collected from Cormorants in Canada from 1995 to 2000. J. Clin. Microbiology, 41: 1280-1284. [Abstract. Sequences encompassing cleavage sites of fusion protein genes were obtained for avian paramyxovirus 1 isolates from cormorants in Canada. All isolates have the virulent cleavage site SRGRRQKR*FVG. They form a distinct cluster within isolates obtained around the world and may represent a novel genotype closely related to genotype V.]


COLLIS K., ROBY D. D. , CRAIG D. P., ADAMANY S., ADKINS J. Y. & LYONS D. E. 2002. Colony size and diet composition of piscivorous waterbirds on the lower Columbia river: Implications for losses of juvenile salmonids to avian predation. Transactions American Fisheries Society, 131(3): 537-550. [Abstract. We investigated colony size and diet composition of piscivorous waterbirds (gulls, terns, and cormorants) nesting on the lower Columbia River from the mouth (river km 0) to the head of McNary Pool (river km 553) in 1997 and 1998. The study was prompted by concern that avian predation might constitute a significant source of mortality to juvenile salmonids Oncorhynchus spp. during out-migration. The diet of California gulls Larus californicus and ring-billed gulls L. delawarensis nesting in colonies above The Dalles Dam (river km 308) included few fish and very few juvenile salmonids. The sole exception was a small colony of California gulls in which salmonids accounted for 15% (by mass) of the diet. Juvenile salmonids were, however, an important component of the diet of colonial waterbirds nesting in the Columbia River estuary. On Rice Island (river km 34), salmonids accounted for 74% (by mass) of the diet of Caspian terns Sterna caspia, 46% for double-crested cormorants Phalacrocorax auritus, and 11% for glaucous-winged-western gulls L. glaucescens × L. occidentalis. Juvenile salmonids were especially prevalent in the diets of colonial waterbirds on Rice Island during April and May. By comparison, juvenile salmonids were significantly less prevalent in the diet of cormorants and gulls nesting lower in the estuary on East Sand Island (river km 8), presumably due to the greater availability of marine forage fishes. Our results indicate that avian predation on juvenile salmonids in the lower Columbia River is more prevalent in the estuary than near the large upriver gull colonies. Furthermore, the high incidence of salmonids in the diets of Caspian terns, cormorants, and gulls nesting on Rice Island suggests that the impact of avian predation on survival of smolts may be reduced by discouraging piscivorous birds from nesting there, while encouraging nesting on East Sand Island and other sites nearer to marine foraging areas.]


Clavijo A. Robinson Y. & Lopez J. Isolation of Newcastle disease virus and Salmonella typhimurium from the brain of double-crested cormorants (Phalacrocorax auritus). AVIAN DISEASES, 45(1): 245-250.

Custer T.W., Custer C.M., Hines R.K., Stromborg K.L., Allen P.D., Melancon M.J. & Henshel D.S. 2001. Organochlorine Contaminants and Biomarker Response in Double-Crested Cormorants Nesting in Green Bay and Lake Michigan, Wisconsin, USA. Arch. Environ. Contam. Toxicol., 40: 89-100. [ref. 2001-4]

Custer, T. W., C. M. Custer, R. K. Hines, S. Gutreuter, K. L. Stromborg, P. D. Allen, and M. J. Melancon. 2001. Do polychlorinated biphenyls contribute to reproductive effects in fish-eating birds? Authors' reply to a Letter to the Editor. Environ. Toxicol. Chem.. 20(6): 1149-1151.

Farquhar J.F. III. 2001. Balancing act: managing cormorants in upstate New York. New York State Conservationist, 56(1): 26-28.

Glahn J.F., Ellis G., Fioranelli P. & Dorr B.S. 2001. Evaluation of moderate and low-powered lasers for dispersing Double-crested Cormorants from their night roosts. In: Brittingham M.C., Kays J. e R. McPeake (eds.). Proceedings of the Ninth Wildlife Damage Management Conference (Pennsylvania State University, 5-8 ottobre 2000): 34-45.

Huner J. V. & Jeske C. 2001. Observations on the occurrence and food habits of Double-crested cormorants and Neotropic cormorants in south Louisiana crawfish ponds: The journal of Louisiana ornithology, 5(1): 22-30.

Jensen A. L. 2001. Modelling the effect of cormorant predation on stocked walleye, Ecological Modelling, 145(2-3): 123-127. [Abstract. A simple model was developed for evaluation of the effects of double-crested cormorant (Phalacrocorax auritus) predation on stocked walleye (Stizostedion vitreum) in the Great Lakes. The model was applied to obtain general relations for stocking and for cormorant predation. If there is no stocking, maintenance of a sizable walleye population is necessary for reproduction, but when the walleye population is maintained by stocking, yield can be increased by fishing the population below the level which produces the maximum sustainable yield without stocking, and the loss in reproduction is made up by stocking. If there is no predation on the stocked walleye, stocking can greatly increase yield. If there is cormorant predation, in the long run the number of cormorants increases with stocking but the number of walleye does not, and stocked walleye are feeding the cormorants.]

Kannan K., Hilscherova K. Imagawa T., Yamashita N., et al. 2001. Polychlorinated naphthalenes, -biphenyls, -dibenzo-p-dioxins, and -dibenzofurans in double-crested cormorants and herring gulls from Michigan waters of the Great Lakes. Environmental Science & Technology, 35(3), 441-447. [Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), naphthalenes (PCNs), and biphenyls (PCBs) were measured in eggs of double-crested cormorants and herring gulls collected from Michigan waters of the Great Lakes. Concentrations of PCNs in eggs of double-crested cormorants and herring gulls were in the ranges of 380-2400 and 83-1300 pg/g, wet wt, respectively.]

Kuiken T. 2001. Watering of Double-crested cormorant chicks. Blue Jay, 59(2): 73-77.

Skagen S.K., Melcher C.P. & Muths E. 2001. The interplay of habitat change, human disturbance and species interactions in a waterbird colony. American Midland Naturalist, 145(1): 18-28. [ref. 2001-1]

Surai P. F., Bortolotti G. R., Fidgett A. L., Blount J.  D. &  Speake B. K. 2001. Effects of piscivory on the fatty acid profiles and antioxidants of avian yolk: studies on eggs of the gannet, skua, pelican and cormorant. Journal of Zoology, 255: 305-312. --- Piscivorous birds consume diets which are rich in highly-polyunsaturated n-3 fatty acids; these play vital roles in embryonic development but are very susceptible to oxidative damage. The effects of such diets on the fatty acid composition and antioxidant content of the yolk were investigated in the northern gannet Morus bassanus, the great skua Catharacta skua, the American white pelican Pelecanus erythrorhynchos and the double-crested cormorant Phalacrocorax auritus. The phospholipid fraction of the eggs of these four species contained high proportions of the n-3 fatty acid, docosahexaenoic acid, which formed 7.5–11.3% (w/w) of the fatty acids of this fraction. The presence of eicosapentaenoic and docosapentaenoic acids also contributed to the total n-3 content of the phospholipid. The n-6 polyunsaturate, arachidonic acid, formed between 8% and 19% (w/w) of the phospholipid fatty acids. For the pelican and cormorant, this is consistent with the consumption of freshwater fishes in which arachidonic acid may be a significant acyl constituent. This finding is, however, more difficult to explain for the gannet and skua which largely consume marine fish with a low arachidonic acid content. The yolks of all four species contained relatively high concentrations of vitamin E (90.2–302.3 [mu]g g[minus sign]1 wet yolk) which was mainly present as [alpha]-tocopherol. The eggs of the pelican and cormorant were especially enriched in carotenoids (150.9 and 115.7 [mu]g g[minus sign]1 wet yolk, respectively). ---

de Voogt P., Dirksen S., Boudewijn T.J., Bosveld A.T.C. & Murk A.J. 2001. Do polychlorinated biphenyls contribute to reproductive effects in fish-eating birds? Letter to the Editor. Environ. Toxicol. Chem., 20(6) :1149.

Wires L.R., F.J. Cuthbert, D.R. Trexel & Joshi A.R . 2001. Status of the Double-crested Cormorant (Phalacrocorax auritus) in North America. Final Report to USFWS. [ref. 2001-2]


Bédard J., Nadeau A. & Lepage M. 2000. Double-Crested Cormorant Culling in the St. Lawrence River Estuary: Results of a 5-Year Program. Technical Bulletin No. 1879, Dec. 1999. [Abstract. Modeling indicated that lowering the double-crested cormorant population from 17,361 to 10,000 pairs could be attained only by a combination of techniques: culling breeding birds in arboreal colonies to lower breeding stock and egg spraying in accessible ground nests to lower recruitment. The 5-year program was launched in 1989; culling was halted 4 years later because the population had fallen below the threshold of 10,000 breeding pairs. A greater vulnerability of males to shooting (203:100) probably accounted for the faster-than-predicted drop in numbers. Egg spraying spanned the entire 5-year period, during which 25,095 nests were treated with inert mineral oil. As predicted by the model, spraying lowered recruitment, but only after a 2-year lag. Culling should be considered a last-resort form of intervention whenever softer techniques (egg spraying, mechanical nest destruction, and carefully planned disturbances to the nesting colonies to enhance predation and abandonment) are not sufficient or practical to produce population control. Population control should be based upon careful planning (included detailed censuses, population modeling, and prior communication with the public) and be conducted under close scientific supervision.]

 Belant J.L., L.A. Tyson & Mastrangelo P.A. 2000. Effects of lethal control at aquaculture facilities on populations of piscivorous birds. Wildlife Society Bulletin, 28(2): 379 - 384. [Ref. 2000-4]

Belyea G. Y., Maruca S. L., Diana J. S., Schneeberger P. J., Scott S. J., Clark Jr. R. D., Ludwig J. P. & Summer C. L. 2000. Impact of Double-Crested Cormorant Predation on the Yellow Perch Population in the Les Cheneaux Islands of Michigan. Technical Bulletin No. 1879, Dec. 1999. [Abstract. The Michigan Department of Natural Resources, in conjunction with the University of Michigan and the U.S. Fish and Wildlife Service, initiated a research study to determine the impact of double-crested cormorants (Phalacrocorax auritus on the yellow perch (Perca flavescens population in the Les Cheneaux Islands area of northern Lake Huron. Aerial and nesting colony counts were conducted to monitor cormorant abundance. We collected 373 cormorants to study food habits via stomach-content analysis. We found that (1) cormorants fed heavily on yellow perch in early spring, but over the entire season only 10 percent of their diet was perch; (2) alewives (Alosa pseudoharengus) and sticklebacks (Culaea inconstans, Pungitius pungitius, Gasterosteus aculeatus) made up the major portion of the cormorants' diet; (3) cormorants removed only 2.3 percent of the available perch biomass (v. 1.8 percent by anglers over the same period); (4) most fish taken by cormorants were less than 150 mm long; (5) total annual perch mortality was about 45 percent, of which less than 9 percent was due to cormorants; and (6) cormorants accounted for only 0.8 percent of the mortality of legal-size perch (> 178 mm), whereas summer sport fishing accounted for 2.5 percent. Thus, although the impact of cormorants on the perch population may vary slightly from year to year, we conclude that cormorant predation has minimal impact on the local perch population.]

Blackwell B.F., Dolbeer R.A. & Tyson L.A. 2000. Lethal control of piscivorous birds at aquaculture facilities in the northeast United States: Effects on populations. North American Journal of Aquaculture, 62(4): 300-307. [ref. 2000-10]

Bur M. T. & Tinnirello S. L. 2000. Diet of Double-Crested Cormorant in Western Lake Erie.Technical Bulletin No. 1879, Dec. 1999. [Abstract. Sport and commercial interest fishing groups are concerned about potential impacts double-crested cormorants (Phalacrocorax auritus may have on fish species. Our objectives for this study were to determine the diet of the cormorant in western Lake Erie and the diet overlap and competition for resources with piscivorous fish, such as walleye (Stizostedion vitreum). The stomach contents of 302 double-crested cormorants collected in western Lake Erie consisted primarily of young-of-the-year gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides) and freshwater drum (Aplodinotus grunniens). In the spring, freshwater drum were the most frequently occurring food in the stomachs and constituted the greatest portion of the diet by weight. Young gizzard shad became the most abundant prey and made up the largest percentage of the diet by weight in the stomachs from the end of July through October. Emerald shiners were abundant in the diet during June, September, and October. The fish species that cormorants ate resembled, by proportion, the species mix found in trawl catches. The diets of cormorants and walleyes were similar from July to October with significant overlap. Results from this study suggest impacts of cormorants at current population levels in Lake Erie are not detrimental to sport and commercial fishing. Therefore, control for the purpose of reducing competition for prey fish with walleye is not warranted at this time.]

Gilbertson M. 2000. Living with Great Lakes chemicals: Complementary strategies and cross-paradigm reconciliation. ECOSYSTEM HEALTH, 6(1): 24-38. [ref. 2000-11]

Glahn J.F., Ellis G., Fioranelli P. & Dorr B.S. 2000. Evaluation of moderate and low/powered lasers for dispersing double/crested cormorants from their night roosts. Pp. 34-45 In: Proc. 9th Wildlife Damage Management Conference, Brittingham M.C., J. Kays & McPeake R. (eds.).

 Glahn J.F., D.S. Reinhold & Sloan C.A. 2000. Recent population trends of Double-crested Cormorants wintering in the delta region of Mississippi: Responses to roost dispersal and removal under a recent depredation order. Waterbirds, 23(1): 38 - 44. [Ref. 2000-3]

Jarvie S., H. Blokpoel & Chipperfield T. 2000. A geographic information system to monitor nest distributions of Double-crested Cormorants and Black-crowned Night Herons at shared colony sites near Toronto, Canada. Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA Technical Bulletin, 1879: 121-129.

Matteson S. W., Rasmussen P. W., Stromborg K. L., Meier T. I., Van Stappen J. & Nelson E. C. 2000. Changes in the Status, Distribution, and Management of Double-Crested Cormorants in Wisconsin. Technical Bulletin No. 1879, Dec. 1999. [Abstract. We reviewed and summarized historical data and conducted population surveys from 1973 through 1997 to determine the breeding status and distribution of double-crested cormorants (Phalacrocorax auritus) in Wisconsin. Breeding cormorants historically occupied large, isolated lakes and wetlands in northern Wisconsin, but there were no known nesting sites until 1919, when cormorants were reported nesting on Lake Wisconsin in south-central Wisconsin. From the 1920's to the 1950's, cormorants occupied 17 colony sites in 16 counties, though no more than 7 sites were occupied during any particular year. From the 1950's to the early 1970's, the number of cormorant nests and colony sites plummeted owing to bioaccumulation of DDT and its metabolites, human persecution at some colony sites, and habitat loss. The installation of 1,269 artificial nesting platforms at 13 locations in north-central, northeastern, northwestern, east-central, and southwestern Wisconsin, coupled with a decline in DDE levels in breeding birds, as well as protection as a State-endangered species, led to a marked recovery. Between 1973 and 1997, the State's breeding population grew at an annual rate of nearly 25 percent, from 66 nests at 3 colony sites to 10,546 nests at 23 colony sites. We estimated population trends for six geographic regions in the State determined by distinct distribution patterns of nesting birds. Cormorant populations for five of six regions increased during 1973 through 1997. Trends differed significantly among regions, with a greater estimated increase in Great Lakes' sites (P < 0.01). In 1997, 81 percent of the State's breeding population occurred on four islands in Green Bay on Lake Michigan. Increasing Lake Michigan cormorant populations have raised concerns among sport and commercial fisheries about impacts on yellow perch (Perca flavescens) although recent studies indicate that alewives (Alosa pseudoharengus) predominate in cormorant diets.]

Matthews C. E. 2000. The Cormorant Controversy. Science Scope, 23(7): 17-

Nisbet I.C.T. 2000. Disturbance, habituation, and management of waterbird colonies - Commentary. WATERBIRDS, 23(2): 312-332. [rif. 2000-15]

Ross R. M. & Johnson J. H. 1999. Fish Losses to Double-Crested Cormorant Predation in Eastern Lake Ontario, 1992-1997. Technical Bulletin No. 1879, Dec. 1999. [Abstract. We examined 4,848 regurgitated digestive pellets of double-crested cormorants (Phalacrocorax auritus) over a 6-year period (1992-97) to estimate annual predation on sport and other fishes in the eastern basin of Lake Ontario. We found more than 51,000 fish of 28 species. Using a model that incorporates annual colony nest counts; fledgling production rates; adult, immature, and young-of-year residence times (seasonal); estimates of mean number of fish per pellet and mean fish size; and a fecal pathway correction factor (4.0 percent), we estimate total annual number of fish consumed by cormorants in the eastern basin of Lake Ontario to range from 37 million to 128 million fish for 1993-97. This fish loss equates to an estimated 0.93 million to 3.21 million kg (mean 2.07 million kg) of fish consumed per year, principally alewife (Alosa pseudoharengus, 42.3 percent) and yellow perch (Perca flavescens, 18.4 percent). Forage fish (alewife, cyprinids, trout-perch {Percopsis omiscomaycus], and other minor components) accounted for 65 percent of the diet, and panfish contributed 34 percent of the diet for the 5-year-period.Gme fish were minor components of the diet, in view of an average estimated annual consumption of 900,000 smallmouth bass (Micropterus dolomieui, 1.1 percent) and 168,000 salmonines (mostly lake trout, Salvelinus namaycush, 0.2 percent). Cormorant predation on lake trout fingerlings stocked in May 1993 and June 1994 was estimated through the use of coded wire tag recoveries from pellets collected on Little Galloo Island 1 and 4 days after stocking events. We estimated losses of 13.6 percent and 8.8 percent. respectively, of the fish stocked for the two events, an average of 11.2 percent. Such losses may be reduced through alteration of existing stocking practices. ]

Shieldcastle, M. C. & Martin L. 2000. Colonial Waterbird Nesting on West Sister Island National Wildlife Refuge and the Arrival of Double-Crested Cormorants. Technical Bulletin No. 1879, Dec. 1999. [Abstract. Recent survey data have shown the importance of West Sister Island National Wildlife Refuge, Lake Erie, to nesting waders. About 40 percent of all herons and egrets nesting in the U.S. Great Lakes are found here, including the Great Lakes' largest colonies of great blue heron (Ardea herodia), great egret (Ardea alba), and black-crowned night-heron (Nycticorax nycticorax), and the largest of two snowy egret (Egretta thula). West Sister Island's importance to Ohio has grown in recent decades with the loss of smaller mainland colonies of waders, especially the black-crowned night-heron. The double-crested cormorant (Phalacrocorax auritus) returned to Ohio as a successful nester in 1992 for the first time in more than a century. The effects of this species on wading bird colonies have been well documented in Canadian Lake Erie. Cormorants have successfully competed against great blue herons for nesting space and eliminated black-crowned night-herons through habitat destruction Nest estimates made at the island since 1991 indicate that the night-heron has fallen to 37 percent of its historic numbers on the island and is dropping dramatically in the region. That species has been affected negatively as canopy height has increased with vegetation succession. A second concern is the cormorant, whose nest counts have increased from 0 to c. 1,5000 in 5 years. This rate of increase mirrors that of East Sister Island, a few kilometers northeast in Canada. To date, competition has not been a significant problem, but habitat degradation has been documented, with major leaf loss noted in 1995 on trees having cormorant nests and along the perimeter of West Sister Island. The Ohio Division of Wildlife and the U.S. Fish and Wildlife Service are concerned, both biologically and esthetically, about the future status of the island's colonies in light of habitat succession and the addition of the cormorant.]

Siegel-Causey D. 2000. The Problems of being Successful: Managing Interactions Between Humans and Double-Crested Cormorants. Symposium on Double-Crested Cormorants, Technical Bulletin No. 1879, Dec. 1999. [Abstract. The natural history, behavior, and ecology of double-crested cormorants (Phalacrocorax auritus) predispose this species for conflict with human sport and commercial fisheries. Cormorants breed early in life, have large broods, are efficient predators even in marginal conditions, seem to be able to adjust colony sizes quickly in response to local conditions, and have limited requirements for feeding and nesting habitats. A survey of the past history of successes and failures in managing cormorants reveals that economic impact is greatest with acquaculture and least in sport fisheries. Research during the past 5 years suggests that some control methods like culling and egg spraying are effective but must be balanced against the actual impacts on humans.]

Simmonds Jr. R.L., Zale A.V. & Leslie Jr., D.M. 2000. Modeled Effects of Double-Crested Cormorant Predation on Simulated Reservoir Sport and Forage Fish Populations in Oklahoma. North American Journal of Fisheries Management, 20(1): 180-

Trapp J. L., Lewis, S.J. & Pence D.M. 2000. Double-crested Cormorant impacts on sport fish: literature review, agency survey, and strategies. Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA Technical Bulletin, 1879: 87-96.

Tyson L. A., Belant J. L., Cuthbert F. J. & Weseloh D. V. 2000. Nesting Populations of Double-Crested Cormorants in the United States and Canada. Technical Bulletin No. 1879, Dec. 1999. [Abstract. Double-crested cormorants (Phalacrocorax auritus) are receiving increasing attention in North America because of depredations of acquaculture facilities and alleged impacts on sport and commercial fisheries. We obtained recent (most since 1994) estimates for the number of nesting double-crested cormorants in the United States and Canada from published references and by conducting telephone interviews with State and Provincial biologists. Using published data, we also determined annual rates of change in the number of cormorants since about 1990. The estimated minimum number of nesting pairs (colonies) of double.crested cormorants was 372,000 (852). Most cormorants nested in the Interior region (68 percent). Overall, double-crested cormorants increased about 2.6 percent annually during the early 1990's. The greates decline (-7.9 percent annual change) was in the West Coast-Alaska region. The greatest increase (6.0-percent annual change) was for the Interior region. THe increase there was primarily a consequence of a 22-percent annual increase in Ontario and U.S. States bordering the Great Lakes. These baseline population data are essential for monitoring trends in nesting populations and for developing informed management decisions. However, the completeness, quality and timing of surveys varied substantially among jurisdictions. Population estimates and rates of changes should, therefore, be used with caution. Methods and timin of future surveys should be coordinated among political jurisdictions (at least within regions) to improve accuracy of estimates and allow more meaningful comparisons of population status.]


 Anonymous. 1999. Cormorant nesting area located in southwest Arkansas. The Catfish Journal 13(11):14.

Bédard J., A. Nadeau & Lepage M. 1999. Double-crested Cormorant culling in the St. Lawrence River estuary: results of a five-year program. p. 147-154. In M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Belyea G.Y., S.L. Maruca, J.S. Diana, P.J. Schneeberger, S.J. Scott, R.D. Clark & Ludwig J.P . 1999. Impact of Double-crested Cormorant predation on the yellow perch population in Les Cheneaux islands of Michigan. p. 47-59. In M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Bur M.T., S.L. Tinnirello, C.D. Lovell & Tyson J.T . 1999. Diet of the Double-crested Cormorant in Western Lake Erie. p. 73-85. In M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Caldwell C.A., Arnold M.A. & Gould W.R. 1999. Mercury Distribution in Blood, Tissues, and Feathers of Double-Crested Cormorant Nestlings from Arid-Lands Reservoirs in South Central New Mexico. Archives of environmental contamination and toxicology, 36(4): 456-

 Custer T.W., Custer C.M., Hines R.K., Gutreuter S., Stromborg K.L., P.D. Allen & Melancon M.J. 1999. Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA. Environmental Toxicology and Chemistry, 18(6): 1209-1217. [Ref 1999-7]

Eckert T.H. 1999. Population trends among yellow perch in the eastern basin of Lake Ontario, 1976-98. Section 10:1-25 in Final Report: to Assess the Impact of Double-crested Cormorant Predation on Smallmouth Bass and other fishes of the Eastern Basin of Lake Ontario. NYSDEC Special Report (February 1, 1999), NYSDEC and USGS. 141 pp.

 Enstipp M.R., Andrews R.D. & Jones D.R. 2000. Cardiac responses to first ever submergence in double-crested cormorant chicks (Phalacrocorax auritus). Comparative Biochemistry and Physiology a Molecular and Integrative Physiology, 124(4) 1999, pp. 523 - 530 . [Ref. 1999-6]

 Glaser L. C., Barker I. K., Weseloh D. V, C., Ludwig J., Windingstad R. M., Key D. W. & Bollinger T.K. 1999. The 1992 epizootic of Newcastle disease in double-crested cormorants in North America. Journal of Wildlife Diseases, 35(2): 319-330. [In the summer of 1992, morbidity and mortality in juvenile double-crested cormorants (Phalacrocorax auritus; DCC) attributable to Newcastle disease virus (NDV) was observed for the first time in seven northern USA states and one Canadian province, and recurred in three western Canadian provinces. Based on clinical signs and laboratory diagnostic findings, DCC mortality from NDV occurred in 59 of the 63 nesting colonies and two of three non-colony sites investigated. An estimate of in excess of 20,000 DCC died, with mortality rates ranging from < 1 to 37% in Great Lakes colonies to 20 to 92% in Minnesota (USA) and North and South Dakota (USA) colonies. Sick juvenile white pelicans (Pelecanus erythrorhynchos) exhibiting signs similar to sick cormorants, and dead pelicans were observed in Minnesota and North Dakota. Mortality rates in pelican colonies were as high as in the adjacent cormorant colonies, but no cause for the mortality of an estimated 5,000 pelicans was determined. No evidence of NDV was found in other species nesting in proximity to affected cormorants. Although the source of the NDV infection is unknown in cormorants, the simultaneous onset of the epizootics in juvenile birds over a wide geographic area implies that the virus was acquired by adults prior to migration and was carried back to nest sites, exposing susceptible nestlings. The possible transmission of this virus from free-ranging wild birds to domestic poultry is a concern. Based on repeated epizootics in cormorants since 1990, NDV seems to be established in DCC.]

Hatch J.J. & Weseloh D.V. 1999. Double-crested Cormorant (Phalacrocorax auritus). In: The Birds of North America, No. 44 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA, USA.

Hutchinson J. 1999. Large cormorant nesting site found in Arkansas. The Aquaculture News 7(9):1-2.

Jarvie S., H. Blokpoel & T. Chipperfield. 1999. A geographic information system to monitor nest distributions of Double-crested Cormorants and Black-crowned Night-herons at shared colony sites near Toronto, Canada. p. 121-129. in M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Johnson J.H., R.M. Ross & Adams C.M. 1999. Diet Composition and Fish Consumption of Double-Crested Cormorants in Eastern Lake Ontario, 1998. NYSDEC Special Report, February 1, 1999. [Ref. 1999-11 - download *.pdf]

 Kuiken T. 1999. Review of Newcastle disease in Cormorants. Waterbirds 22(3): 333 - 347. [Ref. 1999-5]

Kuiken T., Fox G.A. & Danesik K.L. 1999. Bill malformations in double-crested cormorants with low exposure to organochlorines. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, 18(12): 2908-2913.

  Kuiken T., Leighton F.A., Wobeser G. & Wagner B. 1999. Causes of morbidity and mortality and their effect on reproductive successin double-crested cormorants from Saskatchewan. Journal of Wildlife Diseases, 35(2): pp. 331

 Kuiken T., Wobeser G., Leighton F. A., Haines D. M., Chelack B., Bogdan J., Hassard L., Heckert R. A. & Riva J. 1999. Pathology of Newcastle disease in double-crested cormorants from Saskatchewan, with comparison of diagnostic methods. Journal of Wildlife Diseases, 35(1): pp. 8

Matteson, S.W., P. W. Rasmussen, K. L. Stromborg, T. I. Meier, J. Van Stappen & E. C. Nelson. 1999. Changes in the status, distribution, and management of double-crested cormorants in Wisconsin. Pages 27-45 in, Tobin, M. E., Tech. Coordinator, Symposium on Double-crested Cormorants: Population Status and Management Issues in the Midwest. Tech. Bull. 1879, USDA Animal and Plant Health Inspection Service, Washington, DC. [ref. 1999-13]

Reinhold D.S. & Sloan C.A. 1999. Strategies to reduce Double-crested Cormorant depredation at aquaculture facilities in Mississippi. p. 99-105. in M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Ross R.M. & Johnson J.H. 1999. Effect of altered salmonid stocking methods on cormorant predation in eastern Lake Ontario. Sec. 11:1-3 in Final Report: to Assess the Impact of Double-crested Cormorant Predation on Smallmouth Bass and other fishes of the Eastern Basin of Lake Ontario. NYSDEC Special Report (February 1, 1999), NYSDEC and USGS. 141 pp.

Ross R.M. & Johnson J.H. 1999. Fish losses to Double-crested Cormorant predation in Eastern Lake Ontario, 1992-97. p. 61-70. in M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Schneider C. P., Schiavone A. Jr, Eckert T. H., McCullough R. D., Lantry B. F, Einhouse D. W., Chrisman J. R., Adams C. M., Johnson J. H. & Ross R. M. 1999. Double-Crested Cormorant Predation on Smallmouth Bass and Other Fishes of the Eastern Basin of Lake Ontario: Overview and Summary. NYSDEC Special Report – February 1, 1999. [Ref. 1999-12]

Shieldcastle M.C. & L. Martin. 1999. Colonial waterbird nesting on West Sister Island National Wildlife Refuge and the arrival of Double-crested Cormorants. p. 115-119. in M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Trapp J.L., S.J. Lewis & D.M. Pence. 1999. Double-crested Cormorant impacts on sport fish: literature review, agency survey, and strategies. p. 87-96. in M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879. [Ref. 1998-4]

Tyson L.A., J.L. Belant, F.J. Cuthbert & D.V. Weseloh. 1999. Nesting populations of Double-crested Cormorants in the United States and Canada. p.17-25. In M.E. Tobin [ed.] Symposium on Double-crested Cormorants: population status and management issues in the Midwest. USDA/APHIS Tech. Bull. No. 1879.

Wywialowski A.P. 1999. Wildlife-caused losses for producers of channel catfish Ictalurus punctatus in 1996. JOURNAL OF THE WORLD AQUACULTURE SOCIETY, 30(4): 461-472. [Ref. 1999-9]


Adams C. M., Schneider C. P. Johnson J. H. 1998. Predicting the Size and Age of Smallmouth Bass Consumed by Double-Crested Cormorants in Eastern Lake Ontario, 1993-94. NYSDEC Special Report, December 15, 1998.

Agler, B. A., et al. 1999. Decline in marine bird populations in Prince William Sound, Alaska coincident with a climatic regime shift. Waterbirds 22: 98--103. (PO Box 1063, Westbrook, CT 06498, USA; EM: skuas@yahoo.com). ---From1989-1993, loons, cormorants, Melanitta perspicillata, Larus philadelphia, terns, six alcids declined more than 50%, but non-piscivorous Histrionicus histrionicus, Bucephala clangula, Bucephala islandica, and Haematopus bachmani increased 1972 to 1989--1993.---

Cairns, D.K. 1998. Diet of cormorants, mergansers, and kingfishers in northeastern North America. Canadian Tech. Rep. of Fisheries and Aquatic Sciences No. 2225.

Cairns D. K., R. L. Dibblee, & Daoust P.-Y . 1998. Displacement of a large Double-crested Cormorant, Phalacrocorax auritus, colony following human disturbance. Can. Field-Nat. 112: 520--522. (Dept. Fish. Oceans, Box 1236, Charlottetown, PE C1A 7M8, Can.; EM: cairnsd@mar.dfo-mpo.gc.ca ).

 Glahn, J.F., J.B. Harrel and C. Vyles. 1998. The diet of wintering Double-crested Cormorants feeding at lakes in the southeastern United States. Colonial Waterbirds 21(3): 446-452.

Johnson J. H., Ross R. M. &Adams C. M. 1998. Diet Composition and Fish Consumption of Double-Crested Cormorants in Eastern Lake Ontario, 1998. NYSDEC Special Report, December 15, 1998.

King D. T. Harrel J.B. & Reinhold D. 1998. Observations of nocturnal foraging in the Double-crested Cormorant. Colon. Waterbirds 21: 234--235. (USDA, Wildl. Serv., PO Box 316, Stoneville, MS 38776, USA; dtking@netdoor.com).

Kuiken T., F.A. Leighton, G. Wobeser, K.I. Danesik, J. Riva & Heckert R. A. 1998. An epidemic of Newcastle-disease in Double-crested cormorants from Saskatchewan. Journal Wildlife Diseases, 34(3): 457-471.

Kuiken T., Heckert R.A., Riva J., F.A. Leighton & Wobeser G. 1998. Excretion of pathogenic Newcastle disease virus by double-crested cormorants (Phalacrocorax auritus) in absence of mortality or clinical signs of disease. Avian Pathology, 27(6): 541-546. --- Pathogenic Newcastle disease virus (NDV) caused several epidemics of Newcastle disease in double-crested cormorants (Phalacrocorax auritus) in recent years. Eleven 16-week-old cormorants were infected with, or exposed to, pathogenic NDV from one of these epidemics and monitored for 70 days. No birds died, four birds had transient ataxia between 12 and 27 days post-infection (d.p.i.), and one bird had neuronal necrosis and non-suppurative encephalitis characteristic for Newcastle disease. The mean haemagglutination inhibiting antibody titre to NDV peaked at 1: 630, 21 d.p.i., and decreased to 1:56 70 d.p.i. Duration of NDV excretion from the cloaca was 15 +/- 6.2 d.p.i., with a maximum of 28 d.p.i. The absence of mortality in these birds may have been due to age-related resistance. The excretion of NDV by cormorants in the absence of mortality or clinical signs of disease suggests that the cormorant population could maintain pathogenic NDV through serial infection of susceptible birds. The greatest risk of NDV transmission from cormorants to poultry probably is during autumn migration, through contact with infected birds, excreta or contaminated water.

Lantry B. F., Eckert T. H. & Schneider C. P. 1998. The Relationship Between the Abundance of Smallmouth Bass and Double-Crested Cormorants in the Eastern Basin of Lake Ontario. NYSDEC Special Report, December 15, 1998.

Mott D. F., J.F. Glahn, P.L. Smith, D.S. Reinhold, K.J. Bruce & C.A. Sloan. 1998. An evaluation of winter roost harassment for dispersing Double-crested Cormorants away from catfish production areas in Mississippi. Wildl. Soc. Bull. 26: 584--591. (USDA, Wildl. Serv. Prog., Natl. Wildl. Res. Ctr., P.O. Drawer 6099, Miss. State, MS 39762-6099, USA). ---Harassment of Phalacrocorax auritus at night roost sites appeared to reduce their numbers in catfish ponds located within the disturbance area.---

Powell D. C., R.J. Aulerich, J. C. Meadows, M.E. Tillitt De Kelly, K. L. Stromborg, M.J. Melancon, S.D. Fitzgerald & Bursian S.J. 1998. Effects of 3,3',4,4',5-pentachlorobiphenyl and 2,3,7,8-tetrachlorodibenzo-p-dioxin injected into the yolks of Double-crested Cormorant (Phalacrocorax auritus) eggs prior to incubation. Environ. Toxicol. Chem. 17: 2035--2040. (Dept. Anim. Sci., Michigan State Univ., East Lansing, MI 48824, USA.)

Powell D. C. et al. 1998. A photographic guide to the development of Double-crested Cormorant embryos. Colonial Waterbirds, 21: 348--355. (Dept. Anim. Sci., Michigan State Univ., East Lansing, MI 48824, USA; EM(S.J. Bursian): bursian@pilot.msu.edu).

Rail J.-F. & Chapdelaine G. 1998. Food of Double-crested Cormorants, Phalacrocorax auritus, in the Gulf and Estuary of the St. Lawrence River, Quebec, Canada. Canadian Journal of Zoology, 76(4): 635-643. --- Between 1994 and 1996, a total of 613 Double-crested Cormorant (Phalacrocorax auritus) regurgitations were collected at four colonies located in the St. Lawrence Estuary and one colony on the North Shore of the Gulf of St. Lawrence. The diet comprised a great variety of prey, with fishes well represented. Capelin (Mallotus villosus) and sand lance (Ammodytes sp.) together constituted most of the diet, (i.e., frequency of occurrence 66%, numerical frequency 68%, and volume 50%). Sand lance, which were nearly absent in regurgitations from the Estuary, were important in the diet of cormorants from the North Shore of the Gulf. At the North Shore colony, capelin were much more abundant in the diet in 1996 than in 1995, which correlates with independent fisheries data. In contrast to the results of previous studies of this cormorant's diet, our results show a preponderance of schooling fishes over benthic species. We suggest that this reflects a recent trend towards an increase in the abundance of schooling fishes in the St. Lawrence Estuary and Gulf. Overfishing of predatory fishes and oceanographic factors could be involved.

Reinhold D. S., A. J. Mueller & Ellis G . 1998. Observations of nesting Double-crested Cormorants in the Delta Region of Mississippi. Colon. Waterbirds 21: 450--451. (USDA, Anim. Plant Health Inspect. Serv., PO Box 316, Stoneville, MS 38776, USA; EM: david.reinhold@usda.gov). ---Two nest sites of Phalacrocorax auritus found in 1998 annual state waterfowl survey apparently are the 2nd and 3rd known nestings there.---

Ross R. M & Johnson J. H. 1998. Cormorant Predation on Recently Stocked Salmonids at Stony Point, Lake Ontario. NYSDEC Special Report, December 15, 1998.

Ryckman D.P., Weseloh D.V., P. Hamr, G.A. Fox, B. Collins, P.J. Ewins & Norstrom R.J. 1998. Spatial and temporal trends in organochlorine contamination and bill deformities in Double-crested cormorants (Phalacrocorax auritus) from the Canadian Great-Lakes. Environmental Monitoring and Assessment, 53(1): 169-195.

Schneider C. P. & Adams C. M. 1998. Estimating the Size and Age of Smallmouth Bass and Yellow Perch Consumed by Double-Crested Cormorants in the Eastern Basin of Lake Ontario, 1998. NYSDEC Special Report, December 15, 1998.

Sepulveda M. S., R.H. Poppenga, J.J. Arrecis & Quinn L. B. 1998. Concentrations of mercury and selenium in tissues of Double-crested cormorants (Phalacrocorax auritus) from southern Florida. Colonial Waterbirds, 21(1): 35-42. (Dept. Physiol. Sci., Coll. Vet. Med., Univ. Florida, Gainesville, FL 32611, USA; EM: mariesep@ufl.edu). ---Concentrations of over 3 mg/kg ww selenium in liver and over 2 mg/kg mercury in brain in 57% and 37%, respectively, of 99 birds collected 1994--1997 may be causing damage.---


Blackwell B. F. & Krohn W. B. 1997. Spring foraging distribution and habitat selection by Double-crested cormorants on the Penobscot River, Maine Usa. Colonial Waterbirds, 20(1): 66-76.

Blackwell B. F., W. B. Krohn, N. R. Dube & Godin A. J. 1997. Spring prey use by Double-crested Cormorants on the Penobscot River, Maine, USA. Colonial Waterbirds, 20(1): 77-86.

Clayton D.E. & Lovvorn J.R. 1997. Comparison of pellets versus collected birds for sampling diets of Double-crested Cormorants. The Condor, 99(2): 549-553. --- The Authors compared two methods of determining diets of Double-crested Cormorants collected on the North Platte River WY before and after fingerling trout were stocked in the river.

Custer T. W., C. M. Custer & Stromborg K. L. 1997. Distribution of organochlorine contaminants in Double-crested cormorant eggs and sibling embryos. Environmental Toxicology and Chemistry, 16(8): 1646-1649.

Davies J. A., D. M. Fry & Wilson B. W: 1997. Hepatic ethoxyresorufin-O-deethylase activity and inducibility in wild populations of Double-crested cormorants (Phalacrocorax auritus). Environmental Toxicology and Chemistry, 16: 1441-1449.

Derby C. E. & Lovvorn J. R. 1997. Comparison of pellets versus collected birds for sampling diets of Double-crested cormorants. Condor, 99(2): 549-553.

Diana J. S., G. Y. Belyea & R. D. Clark Jr. (Eds.). 1997. History, status, and trends in populations of yellow perch and Double-crested Cormorants in Les Cheneaux Islands, Michigan. Michigan Dep. Nat. Resour. Fish. Div. Spec. Rep. 17, 94 pp.

Farrar J. 1997. Cormorants: maligned, misunderstood and prospering. Nebraskaland 75(4):18-27.

Haffner GD, Straughan CA, Weseloh DV & Lazar R. 1997. Levels of polychlorinated biphenyls, including coplanar congeners and 2,3,7,8,-TCDD toxic equivalents in double-crested cormorant and herring gull eggs from Lake Erie and Lake Ontario: a comparison between 1981 and 1992. J Great Lakes Res 23:52-60

Henshel DS, Martin JW, Norstrom R, Elliott J, Cheng KM & DeWitt J.C. 1997. Morphometric abnormalities in double-crested cormorant chicks exposed to polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls. J Great Lakes Res., 23: 11-26.

Hill S.J., D.K. Cairns, C. Ripley, B. Penak & Arsenault K. 1997. Numbers and diets of double-crested cormorants on the Dunk River in spring of 1993 and 1995. Prince Edward Island Tech Rep. Environ. Sci. No. 3.

Hunt J. D. & Evans R. M. 1997. Brood reduction and the insurance-egg hypothesis in Double-crested Cormorants. Colonial Waterbirds, 20: 485--491. (Dept. Zool., Univ. Manitoba, Winnipeg, MB R3T 2N2, Can.)---Brood reduction at 4-egg Phalacrocorax auritus nests was essentially obligate, with no last-hatched chicks surviving, but survival was greater than in 3-egg nests. Death was caused by non-aggressive competition among siblings.---

Johnson J. H., R. M. Ross & Zingo J. M. 1997. Evidence of secondary consumption of invertebrate prey by Double-crested cormroantss. Colonial Waterbirds, 20(3): 547-551.

Kirsch E. M. 1997. Numbers and distribution of Double-crested cormorants on the Upper Mississippi River. Colonial Waterbirds, 20(2): 177-184.

Korfanty C., W. G. Miyasaki & Harcus J. L. 1997. Review of the population status and management of Double-crested Cormorants in Ontario. Unpubl. rep. Fish Wildl. Branch, Ontario Ministry of Nat. Resour., Peterborough.

Kuiken T., G. Wobeser, F.A. Leighton, I. Shirley & Brown L. 1997. A modular tunnel and blind system to reduce investigator disturbance of breeding colonial waterbirds. Colonial Waterbirds, 20(3): 532-536.

Merrifield K. 1997. Nearshore flights of seabirds past the Yachats River mouth, Oregon. Northwest. Nat., 78: 93-101. (Dept. Bot. Plant Pathol., Oregon State Univ., Corvallis, OR 97331-2902, USA.)---Data for loons, shearwaters, cormorants, pelicans, ducks, and alcids.---

Meteyer C. U., L. C. Docherty De Glaser, J. C. Franson, D. A. Senne & Duncan R. 1997. Diagnostic-findings in the 1992 epornitic of neurotropic velogenic Newcastle-disease in Double-crested cormorants from the Upper Midwestern United-States. Avian Diseases, 41(1): 171-180.

Meyers, R.A. 1997. Anatomy and histochemistry of spread-wing posture in birds. 1. Wing drying posture in the Double-Crested Cormorant, Phalacrocorax auritus. J. Morphol., 233: 67-76.

Neuman J., D. L. Pearl, P. J. Ewins, R. Black, D. V. Weseloh, M. Pike & Karwowski K. 1997. Spatial and temporal variations in the diet of Double-crested cormorants (Phalacrocorax auritus) breeding on the lower Great Lakes in the early 1990s. Canadian Journal of Fisheries and Aquatic Science, 54:1569-1584.

Powell D. C., R.J. Aulerich, J. C. Meadows, J. F. Tillitt De Powell, J. C. Restum, K. L. Stromborg, J. P. Giesy & Bursian S. J. 1997. Effects Of 3,3',4,4',5-Pentachlorobiphenyl (Pcb-126), 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (Tcdd), or an extract derived from field-collected cormorant eggs injected into Double-crested cormorant (Phalacrocorax auritus) eggs. Environmental Toxicology and Chemistry, 16(7): 1450-1455.

Powell D. C., R.J. Aulerich, J. C. Meadows, D.E. Tillitt, K. L. Stromborg, T. J. Kubiak, J. P. Giesy & Bursian S. J. 1997. Organochlorine contaminants in Double-crested Cormorant from Green Bay Wisconsin: II. Effects of an extract derived from cormoran eggs on the chcik embryo. Archives Environmental Contamination and Toxicology, 32: 316-322.

Simmonds R. l., A. V. Zale & Leslie D. M. 1997. Physical and biological factors affecting seasonal Double-crested cormorant densities on Oklahoma reservoirs. Colonial Waterbirds, 20(1): 31-40.

Wildlife Health Centre Newsletter. 1997. Newcastle disease in Cormorants, California, USA – May 1997. Vol 4 (3): 2. Summer.


Blackwell B. F. & Krohn W. B. 1996. The Double-crested Cormorant in Maine - Part II: Is the cormorant a major predator of commercial fishes? Maine Fish and Wildlife Magazine, 38(3): 8-11.

Coon R. A., C. Simonton, E. F. Bowers & J. L. Trapp. 1996. Migratory bird depredation permits issued to southeast aquaculture facilities. Proc. Annu. Conf. Southeast. Assoc. Fish Wildl. Agencies 50.

Glahn J. F. & McCoy B. 1996. Measurements of wintering Double-crested Cormorants and discriminant models of sex. J. Field Ornithol., 66(2): 299-304

Hanbidge B. A. & Fox G. A. 1996. Egg characteristics, growth and developmental landmarks of known age embryos of Double-crested cormorants from Manitoba. Colonial Waterbirds, 19(1): 139-142.

Johnson J. H. & Ross R. M. 1996. Pellets versus feces - their relative importance in describing the food-habits of Double-crested cormorants. Journal of Great Lakes Research, 22(3): 795-798.

King D. T. 1996. Movements of Double-crested Cormorants among winter roosts in the Delta region of Mississippi. J. Field Ornithol., 67: 205-211.

King D. J. 1996. Influence of chicken breed on pathogenicity evaluation of velogenic neurotropic Newcastle-disease virus isolates from Cormorants and Turkeys. Avian Diseases, 40(1): 210-217.

Krohn W. B. & Blackwell B. F. 1996. The Double-crested Cormorant in Maine - Part I: Concerning a study to determine whether or not this controversial Maine nester is a major predator of Atlantic salmon smolts in the Penobscot River. Maine Fish and Wildlife Magazine, 38(2): 8-12.

Larson J. M., W. H. Karasov, L. Sileo, K. L. Stromborg, B. A. Hanbidge, J. P. Giesy, P. D. Jones, Tillitt De Verbrugge D. A. 1996. Reproductive success, developmental anomalies, and environmental contaminants in Double-crested cormorants (Phalacrocorax auritus). Environmental Toxicology and Chemistry, 15(4): 553-559.

McConaughy, M. 1996. First Double-crested Cormorant nesting in Pennsylvania. PA Birds 10: 151. --- One Phalacrocorax auritus nest discovered and photographed in July 1996 on a Susquehanna River island, Dauphin Co.---

Powell D. C., R. J. Aulerich, A. C. Napolitano, K. L. Stromborg & Bursian S. J. 1996. Incubation of Double-crested Cormorant eggs (Phalacrocorax auritus). Colonial Waterbirds, 19: 256--259. (Anim. Sci. Dept., Michigan State Univ., E. Lansing, MI 48824, USA.)---No eggs with blunt end up hatched and only 54% of eggs not manually rotated hatched.---

Pyne L. 1996. Controlling cormorants: has the time come to manage sea birds on Lake Champlain? Vermont Outdoor Magazine. August:16-17.

Russell, I. C., P. J. Dare, D. R. Eaton & J. D. Armstrong. 1996. Assessment of the problem of fish-eating birds in inland fisheries in England and Wales. MAFF (Min. Agric. Fish. Food) Proj. VC0104, Dir. Fish. Res., Lowestoft, England. 130 pp.

Watts B. D. & Bradshaw D. S . 1996. Population expansion by Double-crested Cormorants in Virginia. Raven 67: 75--78. (Ctr. Conserv. Biol., Coll. William & Mary, Williamsburg, VA 23185, USA.)---Phalacrocorax auritus nest numbers increased from 8 to 402 from 1985 to 1995. Describe 5 known breeding sites.---


 Acord B. R. 1995. Cormorant Management and Responsibilities: United States Department of Agriculture. Colonial Waterbirds, 18(Special Publication 1):213-233.

 Aderman A. R. & Hill E. P. 1995. Locations and Numbers of Double-Crested Cormorants Using Winter Roosts in the Delta Region of Mississippi. Colonial Waterbirds, 18(Special Publication 1): 143-151.

Anonymous. 1995. Cormorant Fishing: "Fascinating, But Ultimately Sad". The East, 31(1): 6-

 Bédard J., A. Nadeau & Lepage M. 1995. Double-Crested Cormorant Culling in the St. Lawrence River Estuary. Colonial Waterbirds, 18(Special Publication 1): 78-85.

 Bédard J., A. Nadeau & Lepage M. 1995. Double-Crested Cormorant Morphometry and Field Sexing in the St. Lawrence River Estuary. Colonial Waterbirds, 18(Special Publication 1): 89-90.

Blackwell B. F , W. B. Krohn & Allen R. B. 1995. Foods of nestling Double-crested cormorants in Penobscot-Bay, Maine, Usa - temporal and spatial comparisons. Colonial Waterbirds, 18(2): 199-208.

Blackwell B. F. & Sinclair J. A. 1995. Evidence of secondary consumption of fishes by Double-crested Cormorants. Marine Ecology Progress Series, 123: 1-4.

 Brugger K. E. 1995. Double-Crested Cormorants and Fisheries in Florida. Colonial Waterbirds, 18(Special Publication 1): 110-117.

 Carter H. R., A. L. Sowis, M. S. Rodway, U. W. Wilson, R. W. Lowe, G. J. Mcchesney, E. Gress & Anderson D. W. 1995. Population Size, Trends, and Conservation Problems of the Double-Crested Cormorant on the Pacific Coast of North America. Colonial Waterbirds, 18(Special Publication 1): 189-215.

 Chapdelaine G. & Bédard J. 1995. Recent Changes in the Abundance and Distribution of the Double-Crested Cormorant in the St. Lawrence River, Estuary and Gulf, Quebec, 1978-1990. Colonial Waterbirds, 18(Special Publication 1): 70-77.

 Duffy D. C. 1995. Why Is the double-Crested Cormorant A Problem? Insights from Cormorant Ecology and Human Sociology. Colonial Waterbirds, 18(Special Publication 1): 25-32.

 Erwin R. M. 1995. The Ecology of Cormorants: Some Research Needs and Recommendations. Colonial Waterbirds, 18(Special Publication 1):240-246.

Ewins P. J., D. V. Weseloh & Blokpoel H. 1995. Within-season variation in nest numbers of Double-crested cormorants (Phalacrocorax auritus) on the Great Lakes - implications for censusing. Colonial Waterbirds, 18(2): 179-192.

 Glahn J. E. & Brugger K. E. 1995. The Impact of Double-Crested Cormorants on the Mississippi Delta Catfish Industry: A Bioenergetics Model. Colonial Waterbirds, 18(Special Publication 1): 168-175.

 Glahn J. E. & Stickley A. R. 1995. Wintering Double-Crested Cormorants in the Delta Region of Mississippi: Population Levels and their Impact on the Catfish Industry. Colonial Waterbirds, 18(Special Publication 1): 137-142.

 Glahn J. E., P. J. Dixson, G. A. Littauer & Mccoy R. B. 1995. Food Habits of Double-Crested Cormorants Wintering in the Delta Region of Mississippi. Colonial Waterbirds, 18(Special Publication 1): 158-167.

 Hatch J.J. 1995. Changing Populations of Double-Crested Cormorants. Colonial Waterbirds, 18(Special Publication 1): 8-24.

 Jackson J. A. & Jackson B. J. S. 1995. The Double-Crested Cormorant in the South-Central United States: Habitat and Population Changes of a Feathered Pariah. Colonial Waterbirds, 18(Special Publication 1): 118-130.

 Keith J. A. 1995. Management Policies For Cormorants in Canada. Colonial Waterbirds, 18(Special Publication 1): 234-237.

 King D. T., J. E. Glahn & Andrews K. J. 1995. Daily Activity Budgets and Movements of Winter-Roosting Double-Crested Cormorants Determined by Biotelemetry in the Delta Region of Mississippi. Colonial Waterbirds, 18(Special Publication 1): 152-157.

 Kirsch E. M. 1995. Double-Crested Cormorants Along the Upper Mississippi River. Colonial Waterbirds, 18(Special Publication 1):131-136.

 Krohn W. B., R. B. Allen, J. R. Moring & Hutchinson A. E. 1995. Double-Crested Cormorants in New England: Population and Management Histories. Colonial Waterbirds, 18(Special Publication 1): 99-109.

 Ludwig J. P, H. J. Auman, D. V Weseloh, G. A. Fox,J. P Giesy & Ludwig M. E. 1995. Evaluation of the Effects of Toxic Chemicals in Great Lakes Cormorants: Has Causality Been Established ? Colonial Waterbirds, 18(Special Publication 1): 60-69.

 Milton G. R., P. J. Austin-Smith & Farmer G. J. 1995. Shouting At Shags: a Case Study of Cormorant Management in Nova Scotia. Colonial Waterbirds, 18(Special Publication 1): 91-98.

 Mott D. F. & Boyd E. L. 1995. A Review of Techniques For Preventing Cormorant Depredations At Aquaculture Facilities in the Southeastern United States. Colonial Waterbirds, 18(Special Publication 1): 176-180.

Mott D.F., R.D. Flynt & King J.O. 1995. An evaluation of floating ropes for reducing cormorant damage at catfish ponds. Proc. East. Wildl. Damage Control Conf. 6:93-97.

 Nettleship D. N. & Duffy D. C. 1995. Epilogue: Cormorants, Humans and the Symposium Process. Colonial Waterbirds, 18(Special Publication 1):255-256

 Nettleship D. N. &Duffy D. C. 1995. Cormorants and Human Interactions: An Introduction. Colonial Waterbirds, 18(Special Publication 1):3-6.

 Nisbet L C. T. 1995. Biology, Conservation and Management of the Double-Crested Cormorant: Symposium Summary and Overview. Colonial Waterbirds, 18(Special Publication 1): 247-252.

 Price L M. & Nickum J. G. 1995. Aquaculture and Birds: the Context For Controversy. Colonial Waterbirds, 18(Special Publication 1): 33-45.

Ross R. M. & Johnson J. H. 1995. Seasonal and annual changes in the diet of double-crested cormorants: implications for Lake Ontario’s fishery. Great Lakes Research Review, 2: 1-9.

Simmonds R.L.Jr., A. V. Zale & D. M. Leslie, Jr. 1995. Depredations of catfish by Double-crested Cormorants at aquaculture facilities in Oklahoma, p. 34-37. In R.E. Masters and J.G. Huggins, eds. Twelfth Great Plains Wildl. Damage Control Workshop Proc., Published by Noble Foundation, Ardmore, Okla.

 Stenzel L. E., H. R. Carter, R. P. Henderson, S. D. Emslie, M. J. Rauzon, C. W. Page & O'brien P. Y. 1995. Breeding Success of Double-Crested Cormorants in the San Francisco Bay Area, California. Colonial Waterbirds, 18(Special Publication 1):216-224.

Stickley, A.R.Jr. & J.O. King. 1995. Long-term trial of an inflatable effigy scare device [f]or repelling cormorants from catfish ponds. Proc. East. Wildl. Control Conf., 6: 89-92.

Stickley, A. R., Jr., D. F. Mott, & J. O. King. 1995. Short-term effects of an inflatable effigy on cormorants at catfish farms. Wildl. Soc. Bull. 23: 73--77. (USDA, Anim. Plant Health Inspection Serv., Miss. Res. Stn., P.O. Box 6099, Mississippi State, MS 39762, USA.)---A human effigy was effective in reducing Phalacrocorax auritus numbers at catfish ponds until birds became habituated to it. Effigy use combined with frequent harassment patrols is recommended.---

 Thompson B. C., J. J. Campo & Telfair R. C. 1995. Origin, Population Attributes, and Management Conflict Resolution For Double-Crested Cormorants Wintering in Texas. Colonial Waterbirds, 18(Special Publication 1): 181-188.

 Trapp J. L., T. J. Dwyer, J. J. Doggett & Nickum J. G. 1995. Management Responsibilities and Policies For Cormorants: United States Fish and Wildlife Service. Colonial Waterbirds, 18(Special Publication 1): 226-230.

 Weseloh D. V., P J. Ewins, J. Struger, P. Mineau, C. A. Bishop, S. Postupalsky & Ludwig J. P. 1995. Double-Crested Cormorants of the Great Lakes: Changes in Population Size, Breeding Distribution and Reproductive Output Between 1913 and 1991. Colonial Waterbirds, 18(Special Publication 1): 48-59.

Williams L. L., J. P. Giesy, D. A. Verbrugge, S. Jurzysta & Stromborg K. 1995. Polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in eggs of double-crested cormorants from a colony near Green Bay, Wisconsin, USA. Arch. Environ. Contam.Toxicol., 29: 327-333. [ref. 1995-2]


Banerjee M., W. M. Reed, S. D. Fitzgerald & Panigrahy B. 1994. Neurotropic velogenic Newcastle-disease in Cormorants in Michigan - Pathology and virus characterization. Avian Diseases, 38(4): 873-878.

Ewins P.J. & Weseloh D.V.C. 1994. Effects on productivity of shooting Double-crested Cormorants (Phalacrocorax auritus) on Pigeon Island, Lake Ontario, in 1993. J. Great Lakes Res. 20(4):761-767.

Giesy J. P., Ludwig J. P. & Tillitt D. E. 1994. Deformities in birds of the Great Lakes region. Assigning causality. Environmental Science and Technology, 28: 128A-135A.

Jones P.D., Giesy J.P. & Newsted J.L. 1994. Accumulation of 2,3,7.8-Tetrachlorodibenzo-rho-dioxin Equivalents by Double-Crested Cormorant (Phalacrocorax auritus, Pelicaniformes) Chicks in the North American Great Lakes. Ecotoxicology and environmental safety, 27(2): 192-

Karwowski K. 1994. Food study of the Double-crested cormorant, Little Galloo Island, Lake Ontario, New York, 1992. U.S. Fish & Wildlife Service, Cortland, New York.

MacNeil D. 1994. Feeding habits of cormorants in eastern Lake Ontario. Unpubl. Admin. Rep., New York Sea Grant Extension Program. 12 pp.

Sanderson JT, Norstrom RJ, Elliott JE, Hart LE, Cheng KM & Bellward G.D. 1994. Biological effects of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in double-crested cormorant chicks (Phalacrocorax auritus). J Toxicol Environ Health, 41: 247-265

van den Berg M., Craane B.L.H.J. & Sinnige, T. 1994. Biochemical and Toxic Effects of Polychlorinated Biphenyls (PCBs), Dibenzo-p-dioxins (PCDDs) and Dibenzofurnas (PCDFs) in the Cormorant (Phalacrocorax carbo) After In Ovo Exposure. Environmental toxicology and chemistry / SETAC, 13(5): 803-

 Weseloh D. & Ewins P. J. 1994. Characteristics of a rapidly increasing colony of Double-crested Cormorants (Phalacrocorax auritus) in Lake Ontario: opulation size, reproductive parameters and band recoveries. J. Great Lakes Res. Internat. Assoc. Great Lakes Res., 20: 443-456.


Ankley GT, Niemi GJ, Lodge KB, Harris HJ, Beaver DL, Tillitt DE, Schwartz TR, Giesy JP, Jones PD & Hagley C. 1993. Uptake of planer polychlorinated biphenyls and 2,3,7,8-substituted polychlorinated dibenzofurans and dibenzo-p-dioxins by birds nesting in the lower Fox River and Green Bay, Wisconsin, USA. Arch Environ Contam Toxicol 24:332-344

Anonymous, 1993. The Double Crested Cormorant. Farm pond harvest, 27(1): 10-

Brugger K. E. 1993. Digestibility of three fish species by Double-crested Cormorants. Condor 95: 25--32. (DuPont Agric. Products Exp. Stn., Wilmington, DE 19880-0402, USA; email: BruggeKE@exvax.dnet.dupont.com --- Metabolizeable energy coefficients for fish Ictalurus punctatus (79%), Dorosoma cepedianum (78%), and Lepomis macrochiris (75%) in diet of captive adult Phalacrocorax auritus.---

 Campo J. J., B C. Thompson, J. C. Barron, R. Telfair, P. Durocher & Gutreuter S. 1993. Diet of Double-crested cormorants wintering in Texas. J. Field Ornithol., 64: 135-144.

Roney K. & Longmuir R. 1991. White Pelican and Double-Crested Cormorant Nest Census in Saskatchewan. Blue jay, (51)2: 106-


 Custer T. W. & Bunck C. 1992. Feeding flights of the breeding Double-Crested cormorants at two Wisconsin Colonies. J. Field Ornithol., 63: 203-211.

Forney J. 1993. Some observations on cormorant-fish interactions on Oneida Lake. New York Chapter - American Fisheries Society Newsletter, September 1993, pp. 8–13.

 Glanville E. V. 1992. Cooperative fishing by Double-crested Cormorants, Phalacrocorax auritus. The Canadian Field-Naturalist, 106(4): 522-523.

Hunt J.D., Evans R.M. & Shnier G. 1992. Bald Eagle Predation on Inland Double-Crested Cormorant. Blue jay, 50(2): 115-

Neumann, J. 1992. Report on the collection and analysis of adult Double-crested Cormorant pellets for eastern Lake Ontario, 1992. Unpubl. Admin. Rep., Canadian Wildl. Serv., Burlington, Ontario. 42 pp.

Parkhurst J.A., Brooks R.P. & Arnold D.E. 1992. Assessment of predation at trout hatcheries in Central Pennsylvania. Wildl. Soc. Bull., 20: 411-419.

 Stickley A., G. L. Warrick and Glahn J. F. 1992. Impact of Double-crested cormorant depredation on Channel-catfish farms. Journal Word Aquaculture Society, 23: 192-198.

Tillitt D.E., Ankley G.T., Giesy J.P., Ludwig J.P., Kurita-Matsuba H., Weseloh D.V., Ross P.S., Bishop C.A., Sileo L., Stromborg K.L., Larson J. & Kubiak T.J. 1992. Polychlorinated biphenyl residues and egg mortality in Double-crested cormorants from the Great Lakes. Environmental Toxicology and Chemistry, 11: 1281-1288. [Ref. 1992-1].

Weseloh D. V., P. J. Ewins, J. Neuman &. Ludwig J. P. 1992. Double-crested cormorants of the great Lakes: population changes, diet, fisheries conflicts and band recovery. Colon. Waterbird Soc. Bull.; 16(2): 47-48. (Abstract only).


Conniff R. 1991. Why the catfish farmers want to throttle the crow of the sea. Smithsonian 22(4): 44-55.

Dolbeer R. A. 1991. Migration pattems of double-crested cormorants east of the Rocky Mountains. J. Field. Ornith. 62: 83-93.

Fox G. A., Collins B., Hayakawa E., Weseloh D. V., Ludwig J. P., Kubiak T. J. & Erdman T. C. 1991. Reproductive outcomes in colonial fish-eating birds: a biomarker for developmental toxicants in Great Lakes food chains. II. Spatial variation in the occurrence and prevalence of bill defects in young Double-crested Cormorants in the Great Lakes, 1979-1987. J. Great Lakes Res., 17: 158-167.

James P.C. & Roney K. 1991. New Double Crested Cormorant Colonies in Saskatchewan. Blue jay, 49(1): 27-

 Post W. and Seals C. A. 1991. Breeding biology of a newly-established Double-crested Cormorant population in South Carolina, USA. Colonial Waterbirds, 14: 34-38.

Watson G. E., S. L. Olson & Miller J. R. 1991. A new subspecies of the double-crested cormorant, Phalacrocorax auritus, from San Salvador, Bahama Islands. Proc. Biol. Soc. Wash. 104:356-369.


Boekelheide R. J., D. G. Ainley, H. R. Huber & Lewis T. J . 1990. Pelagic cormorant and double-crested cormorant. Pp. 195-217, in: D. C. Ainley and R. J. Boekelheide (eds.), Seabirds of the Farallon Islands: ecology, dynamics and structures of an upwelling-system community. Stanford Univ. Press, Palo Alto.

Brisse P. 1990. Double-crested Cormorants nesting in Georgia. The Oriole 55 (2 & 3): 42-43.


Bayer R.D. 1989. The cormorant/fisherman conflict in Tillamook County, Oregon. Studies in Oregon Ornithology No. 6.

Bivings A.E., M.D. Hoy & Jones J.W. 1989. Fall food habits of Double-crested Cormorants in Arkansas. Pgs. 142-143. In Ninth Great Plains Wildlife Damage Control Workshop Proceedings. USDA Forest Service General Technical Rep. RM-171.

Doig V., J.M. Hagan & J.R. Walters. 1989. Double-crested Cormorant and Anhinga nesting in the Croatan National Forest. The Chat 53: 1-4.

 Henny C. J., L. J. Blus, S. P. Thompson & Wilson U. W . 1989. Environmental contaminants, human disturbance and nesting of double-crested cormorants in north-western Washington. Colonial Waterbirds 12: 198-206.

Hobson K. A., R W. Knapton & Lysack W. 1989. Population, diet and reproductive success of doubled-crested cormorants breeding on Lake Winnipegosis, Manitoba, in 1987. Colonial Waterbirds, 12(2): 191-197.

.... & Mahoney S. A. 1989. Plumage wettability of the African darter, Anhinga melanogaster, compared with the double-crested cormorant. Ostrich, 60:128-32.

Ludwig J. P., C. N. Hull, M. E. Ludwig & H. J. Auman. 1989. Food habits and feeding ecology of nesting Double-crested Cormorants in the Upper Great Lakes, 1986-1989. Jack-Pine Warbler 67: 117-129.


Campo J. J., B. Thompson, J. C. Barron, P. P. Durocher and Gutreuter S. J. 1988. Feeding habits of double-crested cormorants wintering in Texas. Tex. Parks & Wildl. Dept. Rept., Austin.

 Hennemann W. W. 1988. Energetics and spread-winged behavior in Anhingas and Double-Crested Cormorants: The risks of generalisation. Amer. Zool., 28: 845-851.

 Post W. 1988. Spread of the Double-crested Cormorant into interior of the Southeastern United States. Colonial Waterbirds, 11: 115-116.

Post W. & Post C. A. 1988. Double-crested cormorant nesting in South Carolina. Chat, 52:34-35.

Vermeer K., K. H. Morgan & Smith C. E. J. 1988. Population trends and nesting habitat of Double-crested and Pelagic cormorants in the Strait of Georgia. Pp. 94-98, in F. Vermeer and R. W. ButIer (eds.), The ecology and status of marine and shoreline birds in the Strait of Georgia, British Columbia. Can. Wildl. Serv., Ottawa.


 Craven S. R. & Lev E. 1987. Doubled-crested Cormorants in the Apostle Islands, Wisconsin USA: population trends, food habits, and fishery depredations. Colonial Waterbirds, 10(1): 64-71.

Fox G. A. & Weseloh D. V. 1987. Colonial waterbirds as bio-indicators of environmental contamination in the Great Lakes. ICPB Technical Pubblication, 6:209-216.

Haws K. 1987. Colony expansion and food habits of Double-crested Cormorants. Unpubl. Admin. Rep., Minnesota Dep. Nat. Resour. 6 pp.

King K.A., C.J. Stafford, B.W. Cain, A.J. Mueller & Hall H.D. 1987. Industrial, agricultural, and petroleum contaminants in cormorants wintering near the Houston Ship Channel, Texas, USA. Colonial Waterbirds 10: 93-99.

 Leger C. & McNeil R. 1987. Brood size and chick position as factors influencing feeding frequency, growth and survival of nesting Double-crested cormorant Phalacrocorax auritus. Can. Field. Nat., 101(3): 351-361.

Leger C. & McNeil R. 1987. [Choice of nest placement by double-crested cormorants on the Madeleine Islands, Quebec.]. Can. J. Zool., 65:24-34. (French, English summary).

McNeil R. & Léger C. 1987. Nest-site quality and reproductive success of early- and late-nesting Double-crested Cormorants. Wilson Bull. 99:262-267.

Parkhurst J.A., Brooks R.P. & Arnold D.E. 1987. A survey of wildlife depredation and control techniques at fish-rearing facilities. Wildlife Soc. Bull., 15: 386-394.


Gallant, A. 1986. Summer food of the Double-crested Cormorant (Phalacrocorax auritus L.) on Prince Edward Island: a preliminary report. Unpubl. Admin. Rep., Fish Wildl. Div., Dep. Environ. Resour., Charlottetown, Prince Edward Island. 38 pp.

Price I.M. & Weseloh C. 1986. Increased numbers and productivity of Double-crested Cormorants, Phalacrocorax auritus, on Lake Ontario. Canadian Field-Naturalist 100(4):474-482.

Siegel-Causey D. & Hunt C. L. Jr. 1986. Breeding-site selection and colony formation in double-crested and pelagic cormorants. Auk, 103:230-234.


 Craven S. R. & Lev E. 1985. Double-crested cormorant damage to a commercial fishery in the Apostole Islands, Wisconsin. Proc. East-Wildl. Damage Control Conf., 2: 14-24.

Heinz GH, Erdman TC, Haseltine SD & Stafford C. 1985. Contaminant levels in colonial waterbirds from Green Bay and Lake Michigan, 1975-80. Environ Monitor Assess 5:223-236

 Hennemann W. W. 1985. Energetics, behavior and the zoogeography of Anhingas and Double-Crested Cormorants. Ornis Scandinavica, 16: 319-323.

 Leger C. & McNeil R. 1985. Nest attendance and care of young In double-crested cormorants. Colonial Waterbirds, 8: 96-103.

 Weseloh D. & Struger J. 1985. Massive mortality of juvenile Double-crested cormorants on Little Galloo Island, July 1984. The Kingbird, ??: 98-104.


DesGranges J.L., G. Chapdelaine & Dupuis P . 1984. [Nesting sites and population dynamics of the double-crested cormorant in Quebec.] Can. I. Zool. 62:1260-67. (French; English summary)

Hatch J.J. 1984. Rapid increase of double-crested cormorants nesting in southern New England. Amer. Birds 38:984-88.

 Hennemann W. W. 1984. Spread-winged behaviour of Doubled-crested and Flightless cormorants Phalacrocorax auritus and P. harrisi: wing drying or thermoregulation?. Ibis, 126: 230-239.

Ludwig J. P. 1984. Decline, resurgence and population dynamics of Michigan and Great Lakes double-crested cormorants. Jack-Pine Warbler 62:91-102.

Schramm H.L.Jr., B. French & M. Ednoff. 1984. Depredation of channel catfish by Florida Double-crested Cormorants. Progressive Fish-Culturist 46:41-43.

Vermeer K. & Rankin L. 1984. Population trends in nesting Double-crested and Pelagic cormorants in Canada. Murrelet, 65: 1-9.


 Hennemann W. W. 1983. Environmental influences on the energetics and behavior of Anhingas and Double-Cresetd Cormorants. Physiol. Zool., 56: 201-216.

Milton G. R. & Austin-Smith P. J. 1983. Changes in the abundance and distribution of Double-crested (Phalacrocorax auritus) and Great cormorants (P. carbo) in Nova Scotia. Colonial Waterbirds, 6: 130-138.

Milton G. R. & Austin-Smith P. J. 1983. Population levels and the relationships of Double-crested (Phalacrocorax auritus) and Great (P. carbo) cormorants to the sport and inshore commercìal fisheries of Nova Scotia 1979-80. Unpubl. rep., Nova Scotia Dep. Lands For., Kentville.

Pilon C., J. Burton & McNeil R. 1983. Reproduction du grand cormorant (Phalacrocorax carbo) et du cormorant à aigrettes (P. auritus) aux iles de la Madeleine, Quebec. Can. J. Zool., 61: 524-30.

 Pilon C., J. Burton & McNeil R. 1983. Summer food of the Great and Double-crested Cormorants on the Magdalen Islands, Quebec. Can. J. Zool., 61: 2733-2739.

 Weseloh D. V., S. M. Teeple & Gilbertson M. 1983. Double-crested Cormorants of the Great Lakes: egg-laying parameters, reproductive failure, and contaminant residues in eggs, Lake Huron 1972-1973. Canadian Journal of Zoology, 61: 427-436.


Hatch J.J. 1982. The cormorants of Boston Harbor and Massachusetts Bay. Bird Observer of Eastern Massachusetts 10(2):65-73.

O'Meara T. E., W. R. Marion, O. B. Myers & W. M. Hetrick. 1982. Food habits of three bird species on phosphate-mine settling ponds and natural wetlands. Proc. Annu. Conf. Southeast. Assoc. Fish Wildl. Agencies 36: 515-526.


Blomme C. 1981. Status and breeding success of double-crested cormorant in two North Channel (Lake Huron) colonies in 1979. Ont. Field Biol. 35:70-78.

Bull J. 1981. Double-crested Cormorants breeding at Fishers Island. Kingbird 31:83.

 DesGranges J. L. & Reed A. 1981. Disturbance and control of selected colonies of Doubled-crested cormorants in Quebec. Colonial Waterbirds, 4: 12-19.

Meier T. 1981. Artificial nesting structures for the double-crested cormorant. Wisc. Dept. Nat. Resour. Tech. Bull., 126: 1-13.

 Scharf W. C. & Shugart G. W. 1981. Recent increase in Double-crested Cormorant in the United States Great Lakes. American Birds, 35: 910-911.

Siegel-Causey D. & Hunt C. L. Jr. 1981. Colonial defense behavior in double-crested and pelagic cormorants. Auk, 98:522-31.


Blem C.R., W.H.N. Gutzke & Filemyr C. 1980. First breeding record of the Double-crested Cormorant in Virginia. Wilson Bulletin 92(1):127-128.

Mahoney S. A. 1980. Thermal energetics of double-crested cormorants and anhingas. Am. Zool., 20:734.

1970 - 1979

 Casler C. L. 1973. The air-sac system and buoyancy of the Anhinga and Double-crested cormorant. Auk, 90: 324-340.

 Dunn E. H. 1975. Caloric intake of nestling Double-crested Cormorants. Auk, 92: 553-565.

Dunn E. H. 1975. Growth, body components and energy content of nestling double-crested cormorants. Condor 77:431-38.

Dunn E. H. 1976. Development of endothermy and existence energy of nestling double-crested cormorants. Condor 78:350-56.

Ellison L.N. & L. Cleary. 1978. Effects of human disturbance on breeding of Double-crested Cormorants. Auk 95:510-517.

Gress F., R. W. Risebrough, D. W. Anderson, L. F. Kiff & Jehl J. R. Jr. 1973. Reproductive failures of double-crested cormorants in southern California and Baja California. Wilson Bull. 85:197-208.

Holm S. F., H. D. Irby & Inglis J. M . 1978. First nesting record of double-crested cormorant in Texas since 1939. Bull. Tex. Ornith. Soc. 11:50-51.

Lock A. R. & Ross R. K. 1973. The nesting of the great cormorant (Phalacrocorax carbo) and the double-crested cormorant (Phalacrocorax auritus) in Nova Scotia in 1971. Can. Field-Nat., 87:43-49.

McKenna M.G. & Allard G. E. 1976. Avian mortality from wire collisions. North Dakota Outdoors 39(5):16-18. [Over a three-month period, 244 dead birds were collected under high voltage transmission lines beside two bodies of water in central North Dakota. Recorded mortality was probably underestimated because unknown numbers of carcasses may have been removed by scavengers or may have fallen in inaccessible places, and crippled birds may have swum away undetected. The American coot (88), double-crested cormorant (52), pied-billed grebe (29), and eared grebe (26) were the most commonly killed species. In addition, 18 ducks of 7 species died. The authors suggest that mortality can be minimized with proper planning and routing of power lines, including burying lines or masking lines by structures such as bridges or trees where the lines cross natural flyways. Other ideas presented were establishing power line corridors through which all lines would be routed and creating such demand that technology would be developed and mitigation costs more acceptable.]

Mitchell R. M. 1977. Breeding biology of the double-crested cormorant on Utah Lake. Great Basin Nat., 37:1-23.

Robertson I. 1974. The food of nesting double-crested and pelagic cormorants at Mandarte Island, British Columbia, with notes on feeding ecology. Condor, 76:346-348.

Roney K.N. 1979. Preliminary results of the food consumed by nesting Double-crested Cormorants at Cypress Lake, Saskatchewan. Conference of the Colonial waterbird Group 3: 257-258.

Ross R. K. 1977. A comparison of the feeding and nesting requirements of the great cormorant (Phalacrocorax carbo L.) and the double-crested cormorant (P. auritus Lesson) in Nova Scotia. Proc. Nov. Scot. Inst. Sci., 1974-1976 27:112-14.

Sivak J. G., J. L. Lincer and Bobier W . 1977. Amphibious visual optics of the eyes of double-crested cormorant (Phalacrocorax auritus) and the brown pelican (Pelecanus occidentalís). Can. J. Zool., 55:782-788.

Vermeer K. 1970. Some aspects of the nesting of Double-crested cormorants at Cypress Lake, Saskatchewan, in 1969: a plea for protection. Blue Jay, 28:11-13.

Vermeer K. 1973. Great blue heron and Double-crested cormorant colonies in the Prairie Provinces. Can. Field-Nat., 87:427-432.

1960 - 1969

Anderson D.W. & Hamerstrom F. 1967. The recent status of Wisconsin cormorants. Passenger Pigeon 29(1): 3-15.

Anderson D. W., Hickey J. J., Riseborough R. W., Hughes D. E. & Christensen R.E. 1969. Significance of chlorinated hydrocarbon residues to breeding pelicans and cormorants. Canadian Field-Naturalist, 83: 91-112.

Kury C. R. 1968. Difference in weight of male and female cormorants. Auk 85:513.

Kury C. R. 1969. Pesticide residues in a marine population of double-crested cormorants. J. Wildl. Mgmt. 33:91-95.

Kury C. R. and Cadbury J. M. 1970. The winter distribution of Maine's double-crested cormorants. Auk 87:815.

Lasiewski R. C. and Snyder C. K.. 1969. Responses to high temperature in nestling double-crested and pelagic cormorants. Auk 86:529-40.

Owre O. T. 1967. Adaptations for locomotion and feeding in the anhinga and the double-crested cormorant. Am. Ornithol. Union, Ornithol. Monogr., No. 6.

Vermeer K. 1969. Colonies of Double-crested cormorant and White pelican in Alberta. Can. Field-Nat., 83:36-39.

Vermeer K. 1970. Colonies of Double-crested Cormorants and White Pelicans in Saskatchewan. Canadian Field-Naturalist 84:39-42.

Vermeer K. 1973. Great Blue Heron and Double-crested Cormorant colonies in the Prairie Provinces. Canadian Field-Naturalist 87: 427-432.

Before 1960

Baillie J. L. 1947. The Double-crested Cormorant nesting in Ontario. Canadian Field-Nat. 61: 119-126.

 Bartholomew G. 1942. The fishing activities of Double-crested Cormorants on San Francisco Bay. Condor, 44: 13-21.

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S. Volponi