The energetics of barnacle geese (Branta leucopsis) flying in captive and wild conditions

Experimental data on the relationship between mean heart rate (f(H)) and mean rate of oxygen consumption (V) over dot O-2 of captive barnacle geese during flights in a wind tunnel are assessed in terms of their capacity to predict the typical (V) over dot O-2 of wild barnacle geese, based on the recordings of their f(H), while undertaking autumn migratory flights between Spitsbergen (78degreesN) and Caerlaverock, Scotland (55degreesN). A significant linear relationship has been demonstrated between the f(H) and simultaneously recorded (V) over dot O-2 of a single barnacle goose (B-B) flying in the wind tunnel (V) over dot O-2 = 1.42 f(H) - 304, r(2)=0.82, P<0.001, N=12 flights). Data recorded from three additional geese (N=4 flights), lay within the 95% prediction intervals of the relationship for goose B-B. When these geese (mean body mass= 2.06 kg, n = 4) were flown in the wind tunnel (WT) without the mask, they had a mean f(H) of 451 +/- 23 beats min(-1), yielding an estimate for (V) over dot O-2 of 336+/-33 ml min(-1). However, f(H) has also been recorded from wild barnacle geese (mean migratory f(H) of 253 beats min(-1)), and substitution of this value into the above calibration equation results in an unrealistically low value for mean migratory (V) over dot O-2 of only 55 ml min(-1). Various factors, such as differences in heart mass, selective tissue perfusion, environmental temperature and flock formation, which might account for some of the difference in f(H) between the captive and wild geese are discussed. Comparison with other WT studies shows that inter-species minimum mass-specific (V) over dot O-2 declines with increasing body mass (M-b; range 0.035-2.8 kg) as 173 M-b(-0224), r(2) =0.848. (C) 2002 Elsevier Science Inc. All rights reserved.