Small Gull Identification in Winter

     Along with the recent alcid irruption along New Jersey’s coast, there have been more than the normal sightings of small winter gulls from land.  Four small gulls in particular are Bonaparte’s Gull, Black-headed Gull, Little Gull and Black-legged Kittiwake.  The kittiwake is the only true pelagic gull of this group, so land-based sightings of these are special.  In the adult breeding stage of the four gulls, kittiwake is easy to separate from the other three because it lacks a dark head.  But in subadult stage, all four have a black spot of some sort behind the eye, all have tails with black tips and all sport an “M” pattern to varying degrees on their backs.  Since this is the nonbreeding season, the focus here will be on nonbreeding, or basic, plumage.

Black-legged kittiwake is the least likely to be seen from land here.  It is the largest of the four gulls, but that requires a direct comparison to the others.  Its legs are black; the legs of the other three range from pink/pale to orange/red.  A subadult has a dark spot behind the eyes like the other three, however it is the only one that has a dark half collar around the back of the neck.  In flight, it has an “M” pattern on its back.  The kittiwake’s pattern is bold but is the only one with all white on the outer portion of the upper wings.  The nonbreeding adult is easier to separate from the other gulls as it is the only one with a yellow bill and a black triangle at the wingtips.

First winter black-legged kittiwake.  © S. Weiss

Note bold M pattern on back and the all-white of the wings between the black bars, compared to the wings of the other three gulls.

First winter black-legged kittiwake.  © S. Weiss

Notice the bold black border on the leading edge of the upper wing and the half collar, both lacking in the other three gulls.

First winter black-legged kittiwake.  © S. Weiss

Rarely seen on land.  The half collar, though not so bold in the above photo, is present.

Adult black-legged kittiwake in basic plumage.  © S. Weiss

Note black triangle tip of wings, black legs and yellow bill.

Bonaparte’s gulls are the most commonly seen of the four species.  They are often seen in large flocks, and are often found inland. All ages of nonbreeding Bonaparte’s have a black spot or mark behind the eye.  The sub adult has the “M” pattern on its back, but it is narrow and not as bold as with a kittiwake or little gull.  The adults are the only one of the four with black trailing edges on the top and bottom of the primaries.

Adult Bonaparte's gull in basic plumage.  © S. Weiss

Similar to an adult black-headed gull, but the Bonaparte's has a very narrow black border on the leading edge of the first primary.  It also has a black, not orange, bill.

An adult in basic plumage (top) and a first winter (bottom) Bonaparte's gull.  © S. Weiss

First winter Bonaparte's gull.  © S. Weiss

Very similar to a black-headed gull, but the black-headed gulls inner primaries would be darker.  The Bonaparte's bill is black, and its legs are not bright.

Black-headed gulls are a European and Asian species with limited nonbreeding range to the North Atlantic.  Sightings are usually of an individual bird.  Ironically, the black-headed gull’s alternate plumage hood is a chocolate brown, not black.  That aside, it is very similar to the Bonaparte’s gull in basic plumage.  Subadults share the less bold “M” pattern of the Bonaparte’s but are the only one of the four with all dark inner primaries.  The black-headed gull can also be distinguished from the others with an orange to red bill and orange to red legs.

Adult black-headed gull in basic plumage.  © S. Weiss

Notice the red bill, versus the Bonaparte's black bill, and the dark red legs.

First winter black-headed gull.  © S. Weiss

The M pattern is not as defined as with the other gulls in the group.  Notice the dark color runs deeper from the trailing edge of the wing than on a Bonaparte's gull.  The color of the bill and legs are prominent.  

Adult black-headed gull in basic plumage (center).   © S. Weiss

This bird can be separated from the Bonaparte's on the left by the dark primaries on the under wing.  The red bill is faintly visible too.  They are both adults as there is no black edge to the tails.

Last is the little gull.  There is no smaller gull in the world.  Little gull is mostly an Old World gull, recently expanding to North America.  Little gull sightings are usually of individual birds, often associating with Bonaparte’s gulls.  A nonbreeding adult is the only one of the four with all dark underwings.  This feature can be striking in flight when it is mixed with Bonaparte’s.  Adults also have white border on the top and bottom of the trailing edges of the wings and tip.  The tips of the little gull have a rounded or blunt appearance.  Unlike the others in the group, the little gull carries remnants of its breeding dark hood through the winter.  This smudgy looking cap is found on all ages of the little gull.  The “M” pattern on the first winter little gull is bold like a kittiwake, but also has dark secondaries.  A second winter bird lacks the “M” pattern, but still has white border on the wings trailing edge and white wing tips.

Adult basic plumage little gull.   © S. Weiss

Notice the striking dark under wings, the white border on the trailing edge of the wings on both sides and the rounded tips.

Adult basic plumage little gull.   © S. Weiss

Unlike the Bonaparte's and black-headed gulls, the little gull keeps some remnant of its alternate plumage dark hood in all ages.  That smudgy cap is seen here.

Adult basic plumage little gull.   © S. Weiss

Without seeing the black under wings, this bird is separated easily from adult Bonaparte's and black-headed gulls by the white trailing edge of the wings and its smudgy cap.

Adult basic plumage little gull (left) and Bonaparte's gull (right).  © S. Weiss

Apparent from this photo are the little gull’s uniform gray back, blunted wing tips and dark underwings.  The Bonaparte's gull has white leading edge to upper wing and black only on edge of under wing.