PRODUCTIVITY AND NESTING HABITAT CHARACTERISTICS OF THE BLACK TERN INNORTHERN NEW-YORK

In 1995 and 1996, nest success and nest site selection were investigat ed as part of a study of the breeding biology of the Black Tern (Chlid onias niger), conducted at Perch River Wildlife Management Area (UT?VI A) in Jefferson County, New York, USA. The breeding population at Perc h River WMA increased from 45 pairs in 1995 to 77 pairs in 1996. This likely represents a colony shift. Clutch size was within range for Nor th America and remained stable between years. Mayfield estimates of ne st success in 1995 and 1996 were 35.7% and 44.5%, respectively. Predat ion was the major cause of nest failures during both years. Nest-site habitat data were collected at 20 nests in 1995 (Pontederia cordata) i n 1995 and cattail (Typha spp.) in 1996. Most nests occurred in emerge nt vegetation 26-50 cm tall and in an approximate 50:50 ratio of veget ation cover to open water. The mean water level in 1995 was significan tly higher than in 1996, but was not significantly different at succes sful nests than at failed nests. A habitat model developed in western New York was used to evaluate nest site selection. This model did not predict nests consistently between the 2 years, perhaps due to differe nces in habitat features and/or management practices between two areas .