AVIS-IBIS

Birds of Indian Subcontinent

No sexual differences in embryonic period in jackdaws Corvus monedula and black-headed gulls Larus ridibundus

Publication Type:Journal Article
Year of Publication:2006
Authors:H. Salomons, M, Müller, W, Dijkstra, C, Eising, CM, Verhulst, S
Journal:Journal of Avian Biology
Volume:37
Issue:1
Date Published:2006
ISBN Number:1600-048X
Keywords:Chroicocephalus, Chroicocephalus ridibundus, Coloeus, Coloeus monedula, Corvidae, Corvus, Corvus monedula, Laridae, Larus, Larus ridibundus
Abstract:Offspring survival probability usually decreases with hatching order, especially in species with brood reduction. Brood reduction in combination with a sex difference in embryonic period (the time between laying and hatching of an egg) can potentially have a profound effect on sex allocation, with higher investment in chicks of the early hatching sex because they are more likely to survive to fledge. Two recent studies reported sex differences in the embryonic period, but compared embryonic period between, rather than within, clutches, which does not control for possible environmental effects on both clutch sex ratio and embryonic period. We compared the embryonic period of sons and daughters within clutches in jackdaws Corvus monedula and black-headed gulls Larus ridibundus, two species with frequent brood reduction, and found no sexual difference in embryonic period. This suggests that sex allocation is not affected by sex differences in embryonic period in these species, but more studies are required to verify whether this is a general pattern.
URL:http://dx.doi.org/10.1111/j.0908-8857.2006.03614.x
Short Title:Journal of Avian Biology
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