Diet and growth of glaucous gulls at a large Arctic goose colony

• Published in: Canadian Journal of Zoology
• Main Authors: Samelius, Gustaf, Alisauskas, Ray T
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1999
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic; Karrak Lake; Glaucous Gull; Larus hyperboreus
• Online Access: http://dx.doi.org/10.1139/z99-091; http://www.nrcresearchpress.com/doi/pdf/10.1139/z99-091

We examined the diet and growth of glaucous gull (Larus hyperboreus) chicks at Karrak Lake goose colony in 1994 and were especially interested in how these factors were affected by geese leaving the colony after goose hatch. Insects and bird prey each occurred in about 80% of regurgitated pellets during the first week after hatch of gulls. Thereafter, the frequency of insects in pellets diminished to <20%, whereas the frequency of bird parts and eggshells increased to about 100 and 80%, respectively, and remained high in gull diets during the 6 weeks of this study. We observed no effect of laying order on the size of gull eggs, nor any effects of chick sequence on growth or survival of chicks, suggesting that food was abundant during egg-laying and possibly early in chick rearing. Overall, both the growth rate and final size of chicks varied among nests, and chicks from small broods grew larger than chicks from large broods. Egg size and hatch date had no effect on growth. We suspect that brood size emerged as an important effect on growth, because food abundance declined as gull chicks grew older and brood competition came in to play.