Meeting Abstract

52.3  Saturday, Jan. 5  Re-evaluating parental investment strategies in albatross – a physiological perspective SPRAGUE, R.S.**; ZAUN, B.J.; BREUNER, C.W.; Univ. of Montana; Kauai NWR Complex; Univ. of Montana rachel.sprague@umontana.edu

The pattern of foraging trips made by Procellariiform seabirds during chick rearing allows us to investigate the parental tradeoff between self-maintenance and investment in offspring. Short trips are thought to provide frequent and consistent food for the chick at a net energetic loss to the parent. On the other hand, long trips may augment adult condition while the condition of the chick suffers by less frequent feedings. Parents should modulate the frequency and duration of these foraging trips to maximize lifetime reproductive success. We monitored all chick provisioning trips made by 27 adult Laysan Albatross Phoebastria immutabilis from hatching to fledging (Jan-July). We characterized individual variation in patterns of short (<5 day) and long trips and examined adult body condition and glucocorticoid physiology as potential mechanisms underlying this behavioral variation. Males and females did not differ in any aspect of provisioning behavior. Contrary to expectations, adults with higher condition at the end of incubation and lower percent condition loss during incubation performed a greater total number of long trips (thought to be the strategy of adults in lower condition) during chick rearing. Additionally, adults who made more long trips and a lower ratio of short to long trips had chicks with higher average condition and condition at fledging, and a shallower slope of mass loss approaching fledging; i.e. more long trips (thought to be less beneficial for chicks) correlated with higher than average chick condition indices. We will also investigate glucocorticoid physiology in both the adults and chicks to gain a better understanding of the physiological factors affecting parental investment decisions.