Foraging energetics of Grey‐headed Albatrosses Diotnedea chrysostoma at Bird Island, South Georgia

Abstract

At-sea metabolism (CO2 production) and water turnover of six breeding Grey-headed Albatrosses Diomedea chrysostoma were measured, using the doubly labelled water method, at Bird Island, South Georgia. Mean food consumption (estimated from a water influx rate of 1.01 1 d -' and data on dietary composition) was 12001: d^ ' or 50.4 W. At-sea metabolism (derived from a rate of COz production of 3.98 1 h-') was 27.7 W, 2.5 times the estimated basal metabolic rate (BMR). On average the birds ingested nearly twice as much food energy as they expended to obtain it. The metabolic rate during flight (estimated from at-sea metabolism and activity budget data) was 36.3 W (range 34.7-39.0 W) or 3.2 (range 3.Cb3.4) times the predicted BMR. This is the lowest cost of flight yet measured, but consistent with the highly developed adaptations for economic flight shown by albatrosses. These results are briefly compared with data for other polar vertebrates (penguins, fur seals) exploiting similar prey.A significant part of the costs to parents of rearing offspring is the energy consumed in foraging activities. These costs are likely to be particularly important in species which need to travel long distances (e.g., because they feed on widely dispersed resources) and in species using energetically expensive modes of locomotion (e.g., flapping flight). Although field studies of energy expenditure have been carried out on a variety of birds and mammals (e.g., Mullen 1970, Utter & Lefebvre 1972, Shoemaker et al. 1976, Bryant & Westerterp 1983, little attention has been given to species adapted for long-distance travel. Of birds, pelagic seabirds of the Order Procellariiformes contain many such species and pre-eminent amongst these, in terms of specializations for economy of long-distance flight, are the albatrosses Diomedeidae, which are essentially dependent on soaring and gliding (Pennycuick 1975(Pennycuick , 1982(Pennycuick , 1986. T h e metabolic rate during free-ranging gliding flight has not yet been estimated for any bird; the energy costs of foraging trips have not been measured for any procellariform and there is only one previous study of a seabird, the Sooty T e r n Sterna fusrata (Flint & Nagy 1984).We used the doubly labelled water method, coupled with behavioural and dietary data, to measure the rate of water and energy flux in breeding Grey-headed Albatrosses Diomedea chrysostoma making foraging trips to sea from Bird Island, South Georgia (54"00'S, 38'02'W) during the austral summer of 1983-84. This species has been extensively studied at this site and much information is available on its reproductive biology and ecology (reviewed in Prince 1985), including unique data on activity budgets at sea (Prince & Francis 1984).

Wind, Waves, and Wing Loading: Morphological Specialization May Limit Range Expansion of Endangered Albatrosses

“…Success in exploiting resources in remote regions of the oceans is attributed to morphological adaptations, their ability to soar dynamically (Fig. 1), and their strategic use of wind systems - parasitizing wind and wave energy to minimize energetic costs of flight [5]–[8], and permitting some individuals to circumnavigate the Southern Ocean in just 46 days [9]. However, even albatrosses possess variability in body and wing morphology that have important implications for differential use of wind among species [10] and between sexes within a species [11], [12].…”

Foraging Behavior and Energetics of Albatrosses in Contrasting Breeding Environments

“…Because FMR calculations included time spent at the nest before departure and after arrival at the nest, measured FMR was corrected based on visual observations of departure and arrival times at the nest. Following methods of Costa and Prince (1987), FMR at−sea was calculated as:…”

“…We compiled average FMR and body mass values for Hawaiian and yellow-nosed albatrosses with values from other studies (male and female wandering albatrosses (Shaffer et al, 2001a), shy albatrosses (Thalassarche cauta; Green and Brothers, 1995, Abstract from First International Albatross and Petrel Conference, Hobart, Australia), gray-headed albatrosses (T. chrysostoma; Costa and Prince, 1987), black-browed albatrosses (Thalassarche melanophrys; Shaffer et al, 2004), and Laysan albatrosses during incubation (Pettit et al, 1988) to provide a mechanism for comparing energy expenditure among species (Shaffer, 2011). Given large differences in mass between wandering albatrosses and other studied albatross species, we tested for the effect of genus Diomedea in the relationship between log-transformed FMR and body mass values.…”

“…Albatrosses are well-adapted to long-distance travel due to their economical mode of flight (Pennycuick, 1982;Costa and Shaffer, 2008;Sibly et al, 2012) and anatomical specialization for soaring and gliding (Pennycuick, 1982), which enable low flight costs (Costa and Prince, 1987;Shaffer et al, 2004). Albatross foraging range is variably constrained during the breeding period, however, due to changing energetic requirements at the nest.…”

The effect of food temperature on postprandial metabolism in albatrosses

“…Their reproductive costs are reduced by raising a single chick over 7-8·month periods in the smaller species and 12·months in the Diomedea (Tickell, 1968;Tickell and Pinder, 1975;Thomas et al, 1983;Warham and Sagar, 1998); natal philopatry and lifelong pair bonding minimise many costs associated with breeding. Moult and breeding are mutually exclusive and body moult proceeds very slowly, taking 3-6·years to complete (Tickell, 1968;Brooke, 1981;Prince et al, 1993); and transport costs are typically very low, permitting long-distance foraging at sites very remote from breeding locations (Pennycuick, 1983;Pennycuick, 1987;Weimerskirch et al, 1984;Weimerskirch et al, 2000;Cooper, 1988;Costa and Prince, 1987;). In such a regime, subtle energy gains may result in marginal increases in adult or juvenile survival or in breeding success parameters to which albatross populations have been shown to be very sensitive Robertson, 1991).…”