Red-legged Kittiwake

Overview

The Red-legged Kittiwake is a pelagic gull with one of the most restricted breeding ranges of any North American seabird, nesting almost entirely on a handful of islands in the Bering Sea. It closely resembles the more widespread Black-legged Kittiwake but is slightly smaller, shows a noticeably darker gray mantle, and, as its name indicates, has bright red rather than black legs. Like its relative, it spends the majority of the year far out at sea, coming ashore only to breed on steep cliff ledges.

Because its breeding range is so limited, this species has a much smaller global population than the Black-legged Kittiwake, and any feather or plumage evidence of this species is most likely to originate from the Bering Sea region or adjacent North Pacific waters.

Feather Identification

• Wing feathers: Outer primaries are solid black to the tip with no white mirrors, similar in pattern to Black-legged Kittiwake but set against a visibly darker gray mantle and covert feathers.
• Size and shape: Slightly shorter, more compact flight feathers than Black-legged Kittiwake, consistent with its smaller overall body size; the bill is also proportionately shorter.
• Mantle and covert feathers: Distinctly darker slate-gray than the pale gray of Black-legged Kittiwake, a useful direct comparison when both are seen together.
• Leg feathers/bare parts note: Legs are bright red at all ages past the juvenile stage, the most reliable distinguishing feature from the black-legged relative.
• Compared to similar species: Black-legged Kittiwake is paler-mantled with black legs and a slightly longer bill; the two species can occur together at a few shared colony sites, making leg color the most dependable field mark.

Plumage Details

Adults show a white head and underparts, dark slate-gray mantle and upperwing, solid black wingtips, and bright red legs, with a yellow bill that is shorter and stubbier than that of Black-legged Kittiwake. Nonbreeding adults show only a faint dusky smudge behind the eye. Juveniles show dark markings on the nape and wing coverts similar in pattern to young Black-legged Kittiwakes but set against the darker gray tones typical of the species, along with dusky rather than bright red legs that brighten with age. Adult-like plumage, including full leg coloration, develops over the first few years of life.

Habitat & Range

Red-legged Kittiwakes breed almost exclusively on a small number of islands in the Bering Sea, including the Pribilof Islands, with additional smaller colonies on a few other Bering Sea islands. Outside the breeding season the species is highly pelagic, ranging widely over the North Pacific and Bering Sea, often far from any land. Its extremely restricted breeding distribution makes it one of the more range-limited seabirds of the region.

Behavior & Field Notes

Like other kittiwakes, this species forages at sea, taking small fish and invertebrates near the surface, and is thought to forage more extensively at night than its black-legged relative, a behavior that has been linked to its diet of vertically migrating prey. It nests colonially on narrow cliff ledges, often alongside Black-legged Kittiwakes and other seabirds, building nests from available vegetation and mud. Vocalizations are similar to those of Black-legged Kittiwake, a ringing, repeated call given at the colony. Its restricted range and pelagic habits mean it is rarely encountered outside the Bering Sea and adjacent North Pacific waters.