Bird Finder for April 13: Bonaparte’s Gull

Bonaparte’s Gull
Larus philadelphia

by Milan Bull, Senior Director of Science and Conservation
Spring seems to be the best season when the small, graceful Bonaparte’s Gull frequents our shoreline, flocking sometimes in the hundreds. Unlike other gulls which are often found in mixed flocks, the Bonaparte’s Gulls hang together in separate groups. This tern-like gull, with bright white patches in its wings, breeds in the boreal forest and is the only gull that regularly nests in trees around lakes and marshes.

During the breeding season, “Bonies” are largely insectivorous, picking small insects off the water or catching them on the wing. Along the Connecticut shoreline, as they make their way north, the “Bonies“ can be seen roosting on sandbars, or swirling over the open Sound dipping for zooplankton such as barnacle larvae.

What it looks like: At this season, “Bonies” are often in changing plumage. Most adults will still be in their winter garb, a small gull with a pale grey back and white underparts. Their head is white with a dark eye and a dark ear spot. Others may sport more of the black-headed breeding plumage. In flight look for dark edges to the white primary feathers, immature birds may have a brownish black bar across the base of the wing.

Where to find it: In the spring look for small flocks resting on sandbars along the coast, but especially at Sandy Point and the mouth of the Oyster River, West Haven, and at the freshwater inlet at Southport Beach.