Photo by Ron Holmes
With higher numbers of spring gull migrants arriving, look for flotillas of Bonaparte's Gulls (BOGU) feeding in rip currents. They pick fish off the surface and will occasionally exhibit swallow dives. These birds rarely mix with other gulls. They're one of the smallest gulls, only 11 to 15 inches with a tern-like appearance. This is a beautiful gull with an elegant appearance.
The distinguishing field mark in their winter, non-breeding plumage is a black dot behind each eye. Occasionally in the spring, these birds can be observed transitioning to their breeding plumage with a black head and broken white eye-ring. Their slender bill is always black. They have pink to red legs. In flight their wings show white patches on the outer primaries edged with black. The adult has a pale gray back. First year birds appear brownish on their back, nape and crown. They have a black-tipped tail and show a brownish-black bar at the base of their wings in flight. This bird matures in two years,
sooner than most gulls.
The Bonaparte's Gull is named for French ornithologist, Charles Lucien Bonaparte, a nephew of Napoleon. Charles spent eight years in the early 1800's studying birds in America. This bird is native to North America but is expanding its range to Europe. Its breeding range is Western Alaska across Canada to the Hudson Bay. It spends the winter along the coasts of the United States, in the Southern States and Mexico. This bird breeds in boreal forests choosing open areas along treed edges of bogs, marshes and ponds. The nest is constructed in a conifer 4 to 20 feet up. Occasionally, the nest will be on the ground. Materials consist of twigs, small branches and bark, lined with moss and grasses. Sometimes BOGU will use abandoned nests. Most nests are a platform or shallow saucer shape. Raising a brood of 1 to 4 hatchlings, BOGU will switch their diets to insects on their breeding grounds. Both adults feed their young. Hatchlings are born semiprecocial with eyes open and covered with down. They're able to stand in a day and will leave the nest within two weeks. BOGUs are one of the fastest maturing gulls and are able to breed after their second year.
This gull can be seen in channels and fast moving waterways of Skagit County. They are one of the easiest gulls to identify in our area due to their size, only one year of immature plumage, and unique field marks. Bring your binoculars or scope because these birds are rarely seen on land in Skagit County. Their numbers are highest March through mid-May and August through October in western Washington.