title: Differential autumn migration of the aquatic warbler Acrocephalus paludicola.
abstract: Relatively little attention has been paid to sex differences in the migration of birds in autumn. We studied the autumn migration strategy of molecularly sexed males and females in the globally threatened aquatic warbler Acrocephalus paludicola. We captured 176 birds at a stopover site in the Loire estuary at Donges, France. The median date for the passage of adults was 8 days earlier in males than females, although the timing of migration in first-year males and females was similar. This indicates that males, who are without parental duties, can start their migration earlier than females and first-year birds. Adults were significantly heavier than immature birds but did not have higher fat scores. In both age categories, more males (two to three times more) were captured. However, various factors (including tape-luring) can affect observed sex ratio.
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk, ul. Wita Stwosza 59, 80-308, Gdańsk, Poland, biokwj@univ.gda.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wojczulanis-Jakubas
authors.forename: Dariusz
authors.initials: D
authors.lastname: Jakubas
authors.forename: Julien
authors.initials: J
authors.lastname: Foucher
authors.forename: Joanna
authors.initials: J
authors.lastname: Dziarska-Pałac
authors.forename: Hubert
authors.initials: H
authors.lastname: Dugué
mesh_terms: D000273:Adipose Tissue / Q000502:physiology; D000367:Age Factors; D025041:Animal Migration; D000818:Animals; D049628:Body Size / Q000502:physiology; D005260:Female; D005602:France; D008297:Male; D012621:Seasons; D012737:Sex Factors; D012744:Sex Ratio; D020308:Songbirds / Q000502:physiology*