Relationship between nutritional status and prolactin levels in the Common Eider, a capital incubator
Résumé
In Common Eider, only females incubate while fasting for 25 days. When their body condition is deteriorated at hatching, females often abandon their ducklings. To therefore investigate how body condition may mediate parental care in eiders, we studied the effect of a change in the duration of incubation on their plasma prolactin, i.e. the main parental hormone in birds. Birds with shortened incubation have higher body masses and showed higher levels of plasma prolactin levels at hatching than the control group, suggesting that circulant prolactin at hatching is linked to body condition. The females that underwent an extended incubation started to feed again and displayed a "normal" body mass but unexpectedly a very high plasma prolactin concentration.