Every fall and early winter large numbers of Bonaparte's Gulls congregate in the Puget Sound are of Washington. They are the smallest regularly occurring gull here, and are easily identified by their size, bouyant flight and the white triangle on the leading edge of their upper wings.
We always look flocks over hoping to find a rare Black-headed Gull, Little Gull or Common Gull, but generally have to be satisfied with these little gems.
In the spring and sometimes early fall we see them in their breeding plumage, with their black hood, but in winter they have just the black spot bbehind gtheir eye. These gulls nest well north of here, and build nests in trees!
These gulls reach their adult plumage by the second winter, so when we see them in this plumage we know that they were born the past summer, and are juveniles.
Here is a single Bonaparte's Gull in front of a flock of Heermann's Gulls for size comparison. The Heermann's Gulls are a medium sized gull.
Until next time, good birding.