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Growth and Energy Requirements of Captive-Reared Common Loon (Gavia Immer) Chicks

Fournier, F., Karasov, W. H., Kenow, K. P., and others, 2007, Growth and Energy Requirements of Captive-Reared Common Loon (Gavia Immer) Chicks: Auk, v. 124, no. 4, p. 1158-1167.

Abstract

We measured the energy requirements during postnatal development of six hand- reared Common Loon (Gavia immer) chicks using continuous feeding trials and doubly labeled water. At fledging, the mean ( SE) body mass of chicks was 3,246 51 g. They reached asymptotic body mass in similar to 66 days and had a mean growth rate constant of 0.089 +/- 0.002 day(-1), which was greater than growth rate constants of other, similar-sized precocial birds. Between hatch and day 66, chicks allocated 16.5% of their metabolizable energy to new tissue, lower than the average for other bird species (20%), which might be expected considering their precocial mode of development. There was a developmental change in the assimilation efficiency of food (metabolizable energy coefficient), with a mean of 0.64 +/- 0.03 in chicks aged 21 days, rising to 0.83 +/- 0.07 in chicks aged 35 days.

Keywords:Allocation, Common Loon, Digestion, Gavia Immer, Growth, Metabolizable Energy, Production, Respiration, Salmo-Gairdneri, Rainbow-Trout, Mercury