Publication Abstract

Chick provisioning and chick growth of fulmarine petrels in the Antarctic

Chick provisioning and chick growth of fulmarine petrels in the Antarctic

J.C.S. Creuwels, G.H. Engelhard* and J.A. van Franeker

Seabirds at high latitudes breed in environments with short, but highly productive, summers. Not many species can utilize these narrow windows of time to complete the full breeding cycle, but fulmarine petrels (Procellariiformes, Procellariidae) appear particularly well adapted because of a relatively short period in which they raise their chick. We developed an automatic weighing system with artificial nests to study food provisioning and chick growth. During three seasons (1997-1999), we collected data on chick provisioning of Southern Fulmars (Fulmarus glacialoides) and Antarctic Petrels (Thalassoica antarctica) on Ardery Island (66°S 110°E) near the Australian Antarctic station Casey. Although Southern Fulmars started breeding about 2.5 weeks later than Antarctic Petrels, both were similar in total duration of the breeding period (97 days) and the diet they provide to their chicks. Southern Fulmars delivered meals to their chicks about every 14 hours, almost twice as frequently as Antarctic Petrels. Meal sizes varied between the seasons and species, and averaged from 111g to 152g. On average, Southern Fulmars delivered 240-265 gram per day to their chick, whereas Antarctic petrels delivered 122-140 gram per day. Southern Fulmars were delivering in a more pronounced bimodal distribution pattern and provisioned their chicks more during daytime than Antarctic Petrels. Antarctic Petrels did not compensate their lower chick-feeding rate through larger meals, but their prolonged foraging trips probably enable them to process more of the food into stomach oil and thus produce meals with a higher energy density. Furthermore, Southern Fulma chicks need more energy for thermoregulation ad are thus less efficient in convering food into body mass. By using a “double Gompertz growth model” we were able to investigate both chick growth until peak mass and mass recession until fledging. We investigated the differences in growth between species and how the provisioning and growth parameters were correlated. The average peak mass was 140% of the mean adult mass in Southern Fulmars and 136% in Antarctic Petrels. At fledging, Southern Fulmar chicks were on average 101.5% and Antarctic Petrels chicks 91.7% of the mean adult mass. In Southern Fulmars, the provisioning rate was positively correlated with growth rate, peak mass and fledging mass, but in the Antarctic Petrel these correlations were not significant, probably due to low sample size. The differences in chick provisioning fit in the overall strategies of tw related seabird species that have to adapt to conditions at opposite extremes of their main habitats.

Reference:

J.C.S. Creuwels, G.H. Engelhard* and J.A. van Franeker (2010) Chick provisioning and chick growth of fulmarine petrels in the Antarctic. In: Creuwels JCS (ed), Breeding ecology of Antarctic petrels and southern fulmars in coastal Antarctica. PhD Dissertation, Univ. Groningen, The Netherlands, pp 46–77.

J.C.S. Creuwels, G.H. Engelhard* and J.A. van Franeker

In: Creuwels JCS (ed), Breeding ecology of Antarctic petrels and southern fulmars in coastal Antarctica. PhD Dissertation, Univ. Groningen, The Netherlands, pp 46–77.