Bonaparte’s Gull, named after ornithologist Charles Lucien Bonaparte, not the French emperor, is found across North America, from the northern edge of the boreal forest, where it breeds, to the Gulf of California and Gulf Coast, where it winters. In its leisurely migration, it is often seen across most areas in between. Despite that extensive range, there are no recognized subspecies.
With its black hood in breeding plumage, narrow white eye ring, jet black bill and orange-red legs, it’s not likely to be confused with any other species in North America. It’s behavior is also distinctive: a buoyant, tern-like flight, a bobbing behavior in the water where it frequently dips its bill and head into the water to forage.
Bonaparte’s Gull is odd in that it is the only North American gull species that nests in trees, usually isolated Black Spruce. The nest is usually deep in the branches and not easily visible. This bird’s nest was in the upper third of this tree, but WC only knew because he watched the bird disappear into the branches. Bonaparte’s Gulls can be, but are not always, colonial or semi-colonial nesters. The Peat Ponds, near Fairbanks, for example, usually had 3-4 active nests each year. This species is believed to be a two year gull (two years to sexual maturity).
While the literature doesn’t describe it – Bonaparte’s Gulls are surprisingly poorly studied – WC has witnessed courtship feeding, with the male presenting food to the female, as shown here. The concealed nest is very well made, which is unusual for a gull. It’s constructed by both the male and female, over the course of 7-10 days. There are 2-3 eggs, incubated by both sexes for 22-25 days. Both parents brood the hatchlings, but the brood interval is unknown. Hatchlings fledge in about three weeks. Survival by hatchlings is highly variable.
The estimated world population is 85,000–175,000 pairs, based on analysis of Christmas Bird Counts. But there are reliable observations of flocks of 50,000 or more on San Francisco Bay and 100,000 or more on Lake Erie, and other large aggregations elsewhere. That suggests that even the higher end estimate is conservative. The Alaska population is estimated at several tens of thousands and stable.
The threats to Bonaparte’s Gulls center mostly on the threat of habitat loss as humans alter the boreal forest. But at present, at least, given the large distribution and populations. the IUCN classifies this as a species of Least Concern.
Interior Alaska birders are fortunate: they can visit Smith Lake or the Peat Ponds and see these active, busy birds.
For more bird photographs, please visit WC’s bird photo site, Frozen Feather Images.