Fournier, F., Karasov, W. H., Meyer, M. W., and Kenow, K. P., 2002, Daily energy
expenditures of free-ranging common loon (Gavia immer) chicks: Auk, v. 119, no. 4,
p. 1121-1126. 

Abstract

We measured the daily energy expenditure of free-living Common Loon (Gavia
immer) chicks using doubly labeled water (DLW). Average body mass of chicks
during the DLW measures were 425, 1,052, and 1,963 g for 10 day-old (n = 5), 21
day-old (n = 6), and 35 day-old (n = 6) chicks, respectively, and their mean daily
energy expenditures (DEE) were 686 kJ day(-1), 768 kJ day(-1), and 1,935 kJ day(-1),
respectively. Variation in DEE was not due solely to variation in body mass, but age
was also a significant factor independent of body mass. Energy deposited in new
tissue was calculated from age-dependent tissue energy contents and measured gains
in body mass, which were 51, 54, and 33 g day(-1) from the youngest to oldest chicks.
Metabolizable energy (the sum of DEE and tissue energy) was used to estimate
feeding rates of loon chicks and their exposure to mercury in the fish they consume.
We calculated that loon chicks in Wisconsin consumed between 162 and 383 g wet
mass of fish per day (depending on age), corresponding to intakes of mercury of
16-192 mug day(-1).

Keywords

Contaminants, birds