Birds of Sarcpa Lake, Melville Peninsula, Northwest Territories: Breeding Phenologies, Densities and Biogeography

Forty species of birds were observed during field studies at Sarcpa Lake, Melville Peninsula, N.W.T. during the summers of 1981 and 1982. Evidence of breeding was found for 22 species and the first definite breeding records for the Melville Peninsula were obtained for Glaucous Gull, Pectoral Sandpiper and Semipalmated Sandpiper and Semipalmated Sandpiper. A hybrid pair of gulls (Glaucous x Herring Gull) also nested and this appears to be the first definite North American record of such a hybrid nesting. Fourteen additional breeding species expected to be present, based on maps in Godfrey (1966), were not found. Average breeding bird density (35 pr/sq km) was comparable to that on Bylot Island, but considerably higher than that measured at other High Arctic sites. Neither average breeding bird densities nor phenologies changed appreciably from year to year despite a late spring melt in 1982. In both years birds began their breeding activities as soon as suitable nesting and feeding habitat became available. A biogeographic analysis based on the occurrence of breeding birds at 25 other sites across the Canadian Arctic indicates that the avifauna at Sarcpa Lake is more similar to those of High Arctic island sites than to those of mainland sites, but includes none of the species whose ranges are mainly within the Arctic Archipelago. Key words: arctic biogeography, birds, phenology, nesting density, Melville Peninsula, multivariate analysis