Restoration of body mass in King Penguins after egg abandonment at a critical energy depletion stage: early vs late breeders

• Published in: Journal of Avian Biology
• Main Authors: Robin, Jean‐Patrice, Fayolle, Christine, Decrock, Frédéric, Thil, Marie‐Anne, Côté, Steeve D., Bernard, Servane, Groscolas, René
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: King Penguins
• Online Access: http://dx.doi.org/10.1111/j.0908-8857.2001.320403.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.0908-8857.2001.320403.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0908-8857.2001.320403.x

In fasting‐incubating seabirds, it has been proposed that egg abandonment and refeeding should be induced when a low body mass (BM) threshold is attained, thus ensuring adult survival at the expense of immediate breeding. In the context of life‐history trade‐offs in long‐lived birds, we have tested this hypothesis by comparing short‐term survival and restoration of BM in King Penguins Aptenodytes patagonicus that abandoned their egg to those that were relieved normally by their mate at the end of the first incubation shift. Since King Penguins have an extended laying period, the possible influence of seasonal factors was also examined by comparing early and late breeders. Forty incubating males were experimentally forced to fast until egg abandonment by preventing relief by the female. At egg abandonment of both early and late breeding males, BM was below the BM threshold, fasting duration was eight days (about 30%) longer than for relieved birds, and plasma uric acid level was elevated (signature of increased body protein catabolism, phase III of fasting). All abandoning birds survived and came back from sea at a BM similar to that of relieved penguins. The duration of the foraging trip of abandoning early breeders was the same as that of relieved birds, and some abandoning birds engaged in a new breeding attempt. Abandoning late breeders, however, made foraging trips twice as long as those of relieved males. This difference can be explained by time constraints rather than nutritional constraints, abandoning early breeders having enough time left in the breeding season to engage in a new breeding attempt in contrast to abandoning late breeders. These observations lend support to the suggestion that not only BM but also an internal clock intervene in the decision to engage in breeding or not. By preventing a lethal energy depletion ashore and by acting at a fasting stage where the capacity to restore BM at sea is unaffected, abandonment at a low body condition threshold plays a major role in the trade‐off ...