Biometrics and pre‐migratory fattening in the Snow BuntingPlectrophenax nivalis

Abstract

Biometric data for Snow Buntings overwintering at three sites in Highland Region, Scotland are reported. A significant sexual dimorphism (males larger) was found for eight of nine linear measures of body size recorded (namely wing length, wing span, tail length, tarsus length, bill length to feathers, bill length to nostril, bill width and bill depth); only hind claw length showed no significant sexual dimorphism, mainly because of the variability of this character. Wing lengths of museum skins collected in various parts of the breeding range (Arctic Canada, S.W. Greenland, N.E. Greenland, Iceland and Scandinavia) showed significant variation in males, with those from N.E. Greenland being the largest, but not in females. Skins of males collected in winter in the British Isles were most similar in size to breeding birds of Arctic Canada, S.W. Greenland, Iceland and Scandinavia, and least like those of N.E. Greenland. Weights remained roughly constant for a given site during the winter months, but varied ap...