Morphometrics of the common sandpipers Actitis hypoleucos breeding on the east coast of lake Ladoga

The main morphometric parameters describing the population of the Common Sandpipers Actitis hypoleucos were analyzed. The birds were captured in bringing forth nestlings in June - mid July, 1990–2007. The population of birds of the East coast of Ladoga does not differ from European ones according to its external parameters. Average wing length (N = 178) is 112.8 ± 0.22 (104–120) mm, tail (172) – 57.3 ± 0.22 (49–65 mm), tarso-metatarsus (119) – 24.9 ± 0.12 (21–29) mm, bill (159) – 28.2 ± 0.11 (24–32) mm. Yearling birds nestling for the first time on an average less than older individuals (wing length – 111.9 ± 0.47 mm and 113.3 ± 0.37 mm, respectively), the wings and tails length of senior birds can vary from year to year without any certain tendency. It is established that the wing length is reduced significantly by the end of a breeding season because of the gradual destruction of a plumage. The sizes of females and males overlap almost entirely. It is shown that the birds do not focus on size when forming pairs: the first partner of bird may be either smaller or larger. The effectiveness of sex determination of breeding Common Sandpipers with the help of morphometric indices calculated on the basis of transient birds’ measurements, needs verification as while calculating, the presence of mixed-aged individuals in samples is not considered as well as varying degrees of plumage destruction of females and males migrating in different time periods.