The Food, Feeding, and Development of Young Tufted and Horned Puffins in Alaska

Publisher Website
Google Scholar
Abstract
Aspects of nestling tufted puffin (F. cirrhata) and horned puffin (E. corniculata) feeding ecology, growth rate and fledging success were studied on Buldir Island, Alaska, in 1975 and on Ugaiushak Island, Alaska, in 1976 and 1977. Growth rates were measured for single wide chicks given supplemental food, single chicks raised in captivity and fed ad lib, and for artificially twinned chicks with and without supplemental food and for twinned chicks raised in captivity. Data from these colonies and years (colony years) were compared with those from other colony years for these species and for Atlantic puffins (F. arctica). For most aspects of nestling feeding ecology that have been measured, available data are too variable (seasonally, annually or geographically) to give a reliable correlation with feeding conditions. Growth rates equal to 1.5% of adults body weight/day or less were assoicated with poor feeding conditions while growth rates of 2.5% or more represented optimum feeding conditions. Nestling growth rates currently provide the best means of assessing feeding conditions. The implications of puffins'' ability to raise 2 chicks, rather than their normal clutch of one, are also discussed.