Biometrics and wing moult of migrating Red-rumped Swallows Hirundo daurica in Greece

Published data describing the biometrics, moult and fat loads of migrant Red-rumped Swallows Hirundo daurica are scarce. Here we present data on wing and tarsus length, tail measurements, abdominal fat scores and weight for a sample of 457 birds captured at a reed-bed roost during autumn migration through the island of Lesvos in the gean Sea. Biometrics were similar to those reported from smaller samples of museum skins but with a greater range of values for several measures. Tail length and tailfork length in adult birds were not markedly bimodally distributed, suggesting either that females were rare in the sample captured or that use of the sexing criteria proposed by Svensson (1992) should not be applied to the population migrating through this area. The majority of birds carried fat loads, and these were significantly larger in adult than in first-year birds, suggesting that adults might have been in better condition prior to long-distance migration. Moult of the inner primaries was found in 16.4%, and of tertials in 8.2% of adult birds. Its frequency varied significantly between years, but did not vary with size, mass or fat score.

Jeremy D.Wilson, Triantaphyllos Akriotis, Dawn E. Balmer, Les Hatton and Shirley Millar, Ringing & Migration (2006) 23, 57-61