La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Sexing Blue Tits Parus caeruleus during the winter, with comments on reporting sexing criteria
Auteurs :	David G. C. Harper, Auteur
Type de document :	Article
Dans :	Ringing & Migration (20(2) November, 2000)
Article en page(s) :	111-123
Résumé :	Some suggestions are made about reporting the reliability of sexing criteria, with emphasis on their sensitivities and predictive values. Sexing criteria with imperfect sensitivities have lower predictive value for the rarer sex and can bias estimates of sex ratios. Blue Tits Parus caeruleus wintering in East Sussex were easier to sex than those in a Scottish population (Scott 1993). It is possible that this was because the extent of sexual dimorphism varies between Blue Tit populations; mean wing length appears to vary more between populations among females than among males. Comparisons of the sex ratios of samples caught at different net sites suggested that during the winter females foraged at greater heights than males. Females did not forage significantly further from cover than males, but more data are required.

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