Provisioning and growth rates of Shy Albatrosses at Albatross Island, Tasmania

We used electronic weighing platforms inside artificial nests to remotely study chick provisioning and growth in Shy Albatrosses (Thalassarche cauta) at Albatross Island, Tasmania, from 1996 to 1998. Pairs of birds concurrently carried radio-transmitters, allowing each meal to be attributed to an individual parent. Chicks received relatively small meals (372 g) once every 22 hr, and were provisioned at 392 g day(-1) from the end of the brooding period to fledging. Meal size increased with chick age while the feeding frequency decreased, such that chicks were provisioned at a relatively constant rate until reaching peak mass (5.5 kg at 109 days). Provisioning subsequently declined and chicks lost mass, leaving the nest after 127 days weighing 5.0 kg. Male chicks were fed for 10 days longer than females, they received 27% more food, grew faster, and attained higher peak and fledging masses. Between hatching and fledging, overall food consumption by chicks was estimated at 44.9 kg. Rates of chick provisioning and growth were constant between years. Overall, adult males and females provisioned chicks equally. However, large imbalances were often observed within pairs, and in some cases one parent adjusted its provisioning schedule to compensate for its mate. Adults generally decreased provisioning rates when chicks were well fed, but only some elevated their feeding frequency when faced with greater demands. The ability to increase provisioning to hungry chicks contrasts with expectations from studies of other neritic species.