Bird Fact Friday—Bonaparte’s Gull

Adapted from page 50 of Gulls Simplified:

Bonaparte’s is delicately proportioned overall, with a long-winged profile; a small, round head; and a petite, short, thin, straight, pointy, tern-like bill. In feeding flight, they often impart a potbellied profile when dipping down to the water’s surface to gather food. Initial confusion with terns is not just possible but likely because of their size, physical resemblance, and buoyant flight style. Legs are relatively short compared to those of other North American hooded gulls other than Little Gull.

An adult Boneparte’s Gull, photographed in Churchill, Manitoba around June. This bird is usually 12.3-13.8 inches long, with a wingspan between 30-36 inches.
Photo credit: Kevin Karlson.

In flight, adults show a flashing white triangle on the leading edge of the outer wing, while 1st winter birds have reduced white on the underwing primary tips and black shafts and markings on a white outer wing triangle. Adults have uniformly pale silvery-gray upperparts and white underparts, making the black trailing edge to the outer wing and the black bill stand out.

Bonaparte’s is a small, petite gull with a dainty black bill. This complete breeding plumage is not regularly seen in parts of North America and is seen only briefly at normal migratory locations from April to May. Note the all-black hood (brown in Black-headed Gull), bold white eye arcs, and petite black bill (reddish to black in Black-headed). These nimble gulls commonly perch on elevated platforms, where the pink legs of adults are evident.

 

Gulls Simplified
A Comparative Approach to Identification
By Pete Dunne and Kevin Karlson

This unique photographic field guide to North America’s gulls provides a comparative approach to identification that concentrates on the size, structure, and basic plumage features of gulls—gone are the often-confusing array of plumage details found in traditional guides.

Featuring hundreds of color photos throughout, Gulls Simplified illustrates the variations of gull plumages for a variety of ages, giving readers strong visual reference points for each species. Extensive captions accompany the photos, which include comparative photo arrays, digitized photo arrays for each age group, and numerous images of each species—a wealth of visual information at your fingertips. This one-of-a-kind guide includes detailed species accounts and a distribution map for each gull.

An essential field companion for North American birders, Gulls Simplified reduces the confusion commonly associated with gull identification, offering a more user-friendly way of observing these marvelous birds.

  • Provides a simpler approach to gull identification
  • Features a wealth of color photos for easy comparison among species
  • Includes detailed captions that explain identification criteria and aging, with direct visual reinforcement above the captions
  • Combines plumage details with a focus on size, body shape, and structural features for easy identification in the field
  • Highlights important field marks and physical features for each gull
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