- 15–16.1 in
- 37 in
- 10.8–18.5 oz
- Mouette tridactyle (French)
- The hind toe on the foot of the Black-legged Kittiwake is reduced to a tiny bump, giving the bird its scientific name tridactyla, meaning "three-toed" (instead of four on each foot).
- More predation occurs on Black-legged Kittiwake nests in years of scarce food because the nests are more likely to be left unattended as the parents search for food.
- The Black-legged Kittiwake typically nests on cliff ledges, but will occasionally use man-made structures. It has been known to nest on buildings and shipwrecks.
- The oldest Black-legged Kittiwake ever recorded was at least 20 years, 2 months old, when it was recaptured and rereleased in Alaska.
Nests on cliff ledges of offshore islands, sea stacks, or inaccessible areas of coastal mainland. Winters at sea.
Fish and some marine invertebrates.
- Clutch Size
- 1–3 eggs
- Egg Description
- Brown, blue, gray, olive or tan, with dark brown-gray speckling.
- Condition at Hatching
- Alert and mobile, covered with white and gray down.
Nest composed of wet and dry vegetation and mud (sometimes seaweed, feathers, and barnacles) on top of mud/vegetation platform. Placed on ledge of steep cliff. Nests in colonies.
Feeds in flocks at water surface, mostly in daytime; may dive (shallowly) or snatch food from surface.
Black-legged Kittiwake populations appear stable. The North American Waterbird Conservation Plan estimates 3,126,000 breeding birds in North America and rates them an 8 out of 20 on the Continental Concern Score. They are not on the 2014 State of the Birds Watch List.