Skua (Catharacta, Stercorarius) occurrence in the OSME regionстатья

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1. Sandgrouse29.2.183.pdf Sandgrouse29.2.183.pdf 415,3 КБ 19 декабря 2012 [arkhivov]

[1] Arkhipov V., Blair M. Skua (catharacta, stercorarius) occurrence in the osme region // Sandgrouse. — 2007. — Vol. 29, no. 2. — P. 183–204. Records of skua (Catharacta, Stercorarius) occurrence in the OSME Region come from a wide variety of sources. Those we found in the English language are diverse, but those in the languages of the Region have been difficult, if not impossible, to consult until recent years. The geographic definition of the OSME Region now includes the Caucasus and Central Asian Republics, the majority of whose sources and of those in neighboring Russia and Ukraine have been published only in Cyrillic languages. Offshore observations have been of particular value in suggesting passage trends. Overland passage from skua breeding grounds seems well established, probably as minor migration routes, representing a strategy that would balance better migration conditions against probably uncertain food supplies en route, whereas migrants travelling solely over the sea face poorer migration conditions but may have a guaranteed food supply. Observation of overland migration is rendered more difficult by the underlying trend of fluctuating skua numbers being in delayed lockstep with lemming population cycles. Overland migration between the breeding grounds and the open waters of such as the Aegean, Black and Caspian Seas and of the Gulf through to the Indian Ocean is substantiated by records. Other overland movements, such as across Turkey or eastern Saudi Arabia probably occur, but remain largely undocumented because of low observer density. Furthermore, skuas that do migrate overland probably perform loop migration in at least the southern part of their journey. The recent warming trend of the Holarctic taiga and tundra zones is likely to alter the composition and proportions of their biological communities in an unpredictable and complex way, and probably non-linearly.

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