W. H. Karasov K.P. Kenow M.W. Meyer F. Fournier 2007 <p><span>We measured the energy requirements during postnatal development of six hand-reared Common Loon (</span><i>Gavia immer</i><span>) 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 ≈66 days and had a mean growth rate constant of 0.089 ± 0.002 day</span>⁻¹<span>, 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.</span></p> application/pdf 10.1642/0004-8038(2007)124[1158:GAEROC]2.0.CO;2 en American Ornithological Society Growth and energy requirements of captive-reared Common Loon (<i>Gavia immer</i>) chicks article