Geographical variation in egg size dimorphism in rockhopper penguins ...

• Main Authors: Demongin, Laurent, Poisbleau, Maud, Rey, Andrea Raya, Schiavini, Adrian, Quillfeldt, Petra, Eens, Marcel, Strange, Ian J., Justus Liebig University Giessen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universitätsbibliothek Gießen 2010
• Subjects: Rockhopper penguin; Egg dimorphism; Geographical variation; Chick survival; ddc570; ddc590
• Online Access: https://dx.doi.org/10.22029/jlupub-197; https://jlupub.ub.uni-giessen.de//handle/jlupub/250

All crested penguins present a unique reversed hatching asynchrony: the larger second-laid egg (B-egg) hatches before the smaller first-laid egg (A-egg). Although both eggs often hatch, the A-chick generally dies of starvation within days after hatching. However, within rockhopper penguins, the population at the Falkland Islands is unique in that some birds manage to raise both chicks. Although it has been suggested that the egg size dimorphism between A- and B-eggs may explain how long both eggs and chicks survive, this hypothesis has never been explicitly tested. We expect that both eggs are retained longer in the less dimorphic clutches than in the more dimorphic ones. In this paper, we have compiled egg measurements for three rockhopper penguin species (Eudyptes chrysocome, E. filholi and E. moseleyi) in order to compare the intra-clutch egg size dimorphism among these species. Furthermore, we have collected new data to compare egg size dimorphism between two populations of E. chrysocome (Falkland ...