Distribution and Abundance of Nesting Pairs of Herring Gulls (Larus argentatus) on the North American Great Lakes, 1976 to 2000

摘要: During the past three decades, Canadian and U.S. federal wildlife agencies completed major surveys (1976–1980; 1989–1990; 1998–2000) to census seven species of colonially nesting waterbirds breeding on Great Lakes. We summarize comment distribution abundance herring gulls (Larus argentatus), most widely distributed species. Lake Huron consistently supported highest number pairs, followed by Lakes Superior, Michigan, Erie, Ontario. The pattern four lakes was an increase in numbers between first second censuses, then a decrease third census. Numbers declined each Patterns may be food based although corroborative data are lacking. At colonies censused all periods (1,025 sites representing 80–89% pairs counted), population increased from 63,618 69,975 (first census), 59,590 (last census). low average annual rate change (–0.3%) indicates that gull stable over decades at around 60,000 pairs. identify 20 across where large changes (> 50% two successive periods) were recorded, suggest inter-colony movements could explain among 11 these Michigan. offer examples research protocols use collection limited colony more directly address causes numerical distributional