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The influence of age and sex on wing-tip pattern in adult Black-headed Gulls Larus ridibundus |
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| Authors: | DOMINIQUE ALLAINE JEAN-DOMINIQUE LEBRETON |
| Institution: | Laboratoire de biométrie, Institut d'dnalyse des Systèmes Biologiques et Socioéconomiques, UniversitéClaude Bernard—Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France;Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France |
| Abstract: | A discriminant equation based on bill-depth and total head- and bill-length is provided to sex adult Black-headed Gulls Larus ridibundus . This equation is used to sex birds of known age. Relationships between age and morphometrics and between age and the black extent on the wing are then investigated both in males and females. Size of birds did not change with age but the black extent on the wing tended to decrease with age in both sexes. The tendency to become lighter with age may he an expression of senescence. |
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