The significance of female body stores for egg laying and incubation in Dark-bellied Brent Geese Branta bernicla bernicla

The probability of successful breeding by Brent geese in the Arctic appears to be positively correlated with the mass of females when they depart from spring staging areas in North-western Europe. To clarify the mechanism behind this relationship we investigated the significance of flown-in female body stores for breeding over six summer seasons (1990-1995) in the Pyasina Delta in Taimyr, Russia. Female Brent Geese were caught upon arrival on the breeding grounds. Changes in female body mass and the timing and duration of nest recesses were recorded via electronic weighing platforms placed under their nests. Average female body masses declined through the breeding season, from 1464 g at arrival to 1269 g after egg laying and 1066 g at hatching. Thus half of the stores were used between arrival and clutch completion, the other half during incubation.

Spaans B., van’t Hoff C.A., van der Veer W. & Ebbinge B.S., ARDEA 95 (1): 3-15