Age-dependent differences in iris colouration of passerines during autumn migration in Central Europe

PeerJ

article

Michał Polakowski¹  Krzysztof Stępniewski²  Joanna Śliwa-Dominiak¹  Magdalena Remisiewicz² 

[1] Institute of Biology, University of Szczecin;Bird Migration Research Station, Faculty of Biology, University of Gdańsk

关键词: Autumn migration;    Eye colour;    Age determination;    Body mass index (BMI);   

DOI  :  10.7717/peerj.9188

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Avian eye colour changes with age, but many aspects of this transition are still insufficiently understood. We examined if an individual’s sex, age, species and body condition are related to the iris colour in common migratory passerines during their autumn passage through Central Europe. A total of 1,399 individuals from nine numerous species were ringed and examined in late autumn in northern Poland. Each individual was sexed by plumage (if possible) and assigned to one of three classes of the iris colour—typical for immatures, typical for adults and intermediate. We found that the iris was typical in 97.7% cases of immatures and in 75.8% cases of adults and this difference was significant. Species, sex and body mass index (BMI) had no significant influence on the iris colour. We show that iris colour in passerines in late autumn is strongly age-dependent and thus can serve as a reliable feature for ageing in field studies, especially in species difficult to age by plumage.

【 授权许可】

CC BY