Basal and Field Metabolic Rates of Streaked Shearwater During the Chick-Rearing Period

Abstract

Abstract The energetics of adult Streaked Shearwaters Calonectris leucomelas during the chick-rearing period were examined on Awa Island, Japan, in 2008 and 2009. Basal metabolic rates (BMR) were quantified using an open-flow respirometry system and field metabolic rates (FMR) were quantified using a doubly labelled water (DLW) method. In addition, we used activity loggers to estimate time allocations for different activities at sea. BMR was 0.0124 kJ g-1 h-1 (±0.0153, N=4) on average and corresponded to 54% of the value predicted from allometric equations. FMR was 0.0634 kJ g-1 h-1 (±0.0331, N=3) and was equivalent to 5.1 times BMR, which was higher than values reported for albatrosses (2–4 times BMR). Shearwaters made 50.3 landings a day (±9.8, N=12) and spent 44.8% (±8.0, N=12) of their time sitting on the water. They landed on water approximately twice as often as albatrosses (which have been well-studied using DLW), but they both spent similar proportions of their time on water. Frequent landings at ...