Black Guillemot

The black guillemot, or tystie, is a medium-sized seabird from the Alcidae family, with a length of 30 to 32 centimeters and a wingspan of 52 to 58 centimeters. Weighing between 300 to 460 grams, this bird exhibits a striking dichotomy in plumage between seasons. During the breeding season, it dons a sleek black coat with a prominent white patch on the upper wing. The legs, feet, and interior of the mouth radiate a bright coral-red, and the beak is jet black. As autumn approaches, the guillemot transitions to a winter wardrobe of pale grey and white barred upperparts, a grey head, white underparts, and paler red extremities, though the white wing patch and black beak persist.

Identification Tips

In the field, the black guillemot can be identified by its black summer plumage with a distinctive white wing patch, and coral-red feet and gape. In winter, look for the light grey and white barred pattern on the back and shoulders, and the pale red legs and feet. Juveniles and immatures are marked by their white wing patch speckled with grey or brown, visible even from a distance.

Habitat

The black guillemot favors rocky shores for breeding, utilizing cliffs and boulders for nesting. It is often seen in inshore waters, diving for benthic prey.

Distribution

This circumpolar species is found across the boreal, low arctic, and high arctic regions of the North Atlantic and Arctic Oceans. It breeds as far south as the Gulf of Maine and New England in North America, and in Europe from the British Isles northward. Notably, it is one of the few birds to colonize Surtsey, the nascent volcanic island off Iceland.

Behaviour

The black guillemot is known for its underwater foraging, diving from the surface to pursue fish, crustaceans, and other marine delicacies. It is a solitary or pair-oriented bird, often seen carrying its catch for extended periods.

Song & Calls

During the breeding season, the black guillemot emits a high-pitched whistle, with the red gape also being particularly noticeable.

Breeding

Breeding begins between late February and early May, with pairs or small groups laying two-egg clutches. Incubation lasts 28 to 32 days, and chicks are cared for until fledging at 30 to 40 days old. Independence is immediate upon fledging, with birds returning to their natal colonies at three to four years of age.

Similar Species

The black guillemot can be confused with other auks, but its distinctive wing patch and red feet during the breeding season are key differentiators.

Diet and Feeding

A diet rich in fish and crustaceans characterizes the black guillemot, with occasional mollusks, insects, and plant matter supplementing its meals.

Conservation status

The IUCN Red List categorizes the black guillemot as a species of Least Concern, indicating a stable population without significant immediate threats to its survival.