Beskaravainyi, M.M., Kostin, S.Yu. 1998

[Distribution, numbers and some peculiarities of the breeding ecology of the Shag and the Herring Gull in the South-Eastern Crimea.] In Russian with English summary.

Berkut. 7 (1-2). 25-29.

The Shag and the Herring Gull form a basis of hydrophilous breeding ornithocomplex of the Southern Crimea coast, where they inhabit rocky coast precipices and small rocky islands. Seven areas of nesting of the Shag have been found (170-180 pairs): the largest one at the Karadag Nature reserve. For nesting wider range relief elements are used, than at the North coast; inland components are used more often to build the nests. Periods of the reproductive cycle vary within 2,5 months for different pairs and starts at the end of February. The Herring Gull inhabits the six main areas (about 150 pairs). Distinctive feature of biotopes in this region is the significant development of relief vertical elements. The reproductive cycle starts in April. During the last decade, invasion of new habitats and increase of abundance at the South coast has been being observed. The food mostly consists of animal organisms that are collected on the coastal zone.

Key words: Shag, Herring Gull, the Crimea, distribution, numbers, ecology, breeding, feeding.

Address: M.M.Beskaravainyi, Karadag Nature Reserve, 334876 PO Kurortnoe, Feodosiya, the Crimea, Ukraine.

Dawson A.

Mechanisms of endocrine disruption with particular reference to occurrencein avian wildlife: A review

ECOTOXICOLOGY 2000 - 9(1-2): 59-69

Abstract: This review examines the evidence for endocrine disruption in birds. It rev iews in vitro and in vivo laboratory based evidence for endocrine disruptio n by (1) agonism or antagonism of gonadal steroid hormones, (2) altering th e activity of cytochrome P450 enzymes, (3) altering thyroid hormone functio n, (4) affecting intrinsic neuroendocrine control mechanisms and (5) activa tion of the stress response. It also discusses the evidence for the existen ce of such effects in free-living birds. In vitro studies demonstrate that mechanisms for potential endocrine disruption exist, but in vivo studies su ggest that such mechanisms are insufficient to overwhelm endogenous homeost atic control. There are only two phenomena in wild birds where endocrine di sruption has been cited as a possible cause: eggshell thinning and supernor mal clutches. Evidence suggests that neither of these is caused by endocrin e disruption. Despite three decades of concern, there is no evidence that a vian wildlife has suffered endocrine disruption.

Keywords: endocrine disruption; birds; steroid hormones; P450; thyroid;

Address: Dawson, A Ctr Ecol & Hydrol, Monks Wood, Huntingdon PE28 2LS, Cambs, England Ctr Ecol & Hydrol Monks Wood Huntingdon Cambs England PE28 2LS d