Basal metabolic rate and thermal conductance in Arctic Tern chicks and the effect of heat increment of feeding on thermoregulatory expenses

Arctic Tern (Sterna paradisaea) Science Article 2

abstract

Chick basal metabolic rate (BMRc) as oxygen consumption (VO2 in ml O2 g-1 h-1) of unfed individuals of Arctic Terns Sterna paradisaea during development (12-109 g) was best described by the parabolic equation VO2 = 1.25 + 0.061 m-0.00047m2, where m is body mass in g. Interspecific comparison of hatchling BMRc revealed a relatively high MBRc in Arctic Tern hatchlings, in accordance with an increase in BMRc, with latitude for hatchling terns (Fig. 5). Thermal conductance (h in ml O2 g-1 h-1.degree.C-1). In the chicks was best described by the equation: h = 1.21 m-0.486. In chicks the heat increment of feeding (HIF) in the thermoneutral zone was 1.04 ml O2 g-1 h-1 and not distinguishable from the HIF of 0.92 ml O2 g-1 h-1 at temperatures below the lower critical temperature. The apparent absence of a compensation of thermoregulatory costs with the HIF, is suggested to be due to a more peripherally located thermosensitivity in chicks as compared to adults.

Klaassen M., Bech C. & Slagsvold G, ARDEA 77 (2): 193-200.

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