Biometrics of adult Grey Plovers Pluvialis squatarola breeding in the Lena Delta, NE-Siberia (The Sakha republic, Yakutia)

Abstract

The Grey Plover Pluvialis squatarola is a circumpolar breeding wader with slight clinal but discontinuous morphometric variations in the Palearctic. Birds breeding in eastern Siberia seem to be larger than birds breeding in western Siberia as well as those breeding in northern Canada and Alaska. Biometric data on 15 Grey Plovers trapped in the Lena Delta 1997 are supplied. In all morphometrical measurements females were on average larger than males, and significant differences occurred for tarsus length (48.1 vs 45.9mm). Furthermore, during incubation females were significantly heavier than males (228.9 vs 217.7g). Sexes could be distinguished by discriminant functions. Most measurements support the view that Palearctic birds are larger than Nearctic ones, but differentiation within the Palearctic remains obscure. Wing, tarsus and bill length of the Lena birds correspond with data from western Siberian birds rather than from eastern Siberia/Alaska; bill length coincides with measurements from Wrangel Island. Besides sex-specific and geographical differences, migration routes and location of overwintering areas are discussed. © 2001 British Trust for Ornithology.