SEX-RELATED AND AGE-RELATED BIOMETRIC VARIATION OF BLACK-HEADED GULLSLARUS-RIDIBUNDUS IN WESTERN-EUROPEAN POPULATIONS

Citation
Le. Palomares et al., SEX-RELATED AND AGE-RELATED BIOMETRIC VARIATION OF BLACK-HEADED GULLSLARUS-RIDIBUNDUS IN WESTERN-EUROPEAN POPULATIONS, Bird study, 44, 1997, pp. 310-317
Citations number
13
Categorie Soggetti
Ornithology
Journal title
ISSN journal
00063657
Volume
44
Year of publication
1997
Part
3
Pages
310 - 317
Database
ISI
SICI code
0006-3657(1997)44:<310:SAABVO>2.0.ZU;2-#
Abstract
A multivariate discriminant analysis was performed with biometric data from 583 Black-headed Gulls Larus ridibundus of known sex, either win tering in central Spain or wintering and breeding in The Netherlands. The discriminant function calculated from these birds was applied to 1 158 Black-headed Gulls trapped in Madrid; age, sex and temporal differ ences in biometrics were analysed for those birds. All measurements ta ken varied significantly between the sexes, but head-and-bill length a nd bill depth were the best discriminant variables. Bone measurements (bill length, head-and-bill length, and tarsus length) did not vary be tween first-or second-winter birds or adults. In contrast, wing length , length of the eighth primary, mass and bill depth increased signific antly with age for both sexes, although females attained their final s ize quicker than males. Both wing length and body condition increased throughout the winter. Possible explanations for these results are dis cussed.