Razorbill
Razorbills are a study in stark contrasts— not only in their striking, sharply-defined black-and-white plumage, but also in their amazing life history. Razorbills spend most of the year solitary and silent at sea, but every breeding season gather on land in dense colonies, forming strong pair bonds and exhibiting complex social behavior. Pairs tend a single egg, whose hatching leads to a series of the most remarkable contrasts of all: the Razorbill's transition from utter helplessness as a nestling, to a highly unusual intermediate flightless stage at sea, to independence.

Razorbills breed on islands and coasts of eastern North America, including Maine and the Atlantic provinces of Canada, as well as isolated locations along the Hudson Strait. North American Razorbills winter south of their breeding range in coastal and continental-shelf waters (typically 20 to 40 meters deep), in large numbers from the Bay of Fundy to Georges Bank, and more sparsely as far south as waters off Long Island and New Jersey.
Razorbill Range Map

About two-thirds of the world's population of Razorbills breeds in Iceland. The species also breeds in northwest Greenland, the Faeroe Islands, the British Isles, as well as Scandinavia and northern Russia. Razorbills winter in large numbers in the North Sea and in Danish waters, as well as the Baltic Sea. They also occur in winter in the Irish Sea south as far as the western Mediterranean.

Throughout its range, but especially in North American waters, Razorbill populations faced severe pressures in the early 20th century from hunting and egg harvesting by humans. Since 1917, the Migratory Bird Treaty Act has largely protected Razorbills in the northwest Atlantic from such activity, and after a period of slow recovery, populations appear now to be increasing.

Razorbills feed on schooling fish. They generally forage 5 to 30 meters below the surface, though they occasionally dive to depths greater than 100 meters. Razorbills flick their wings to propel themselves after prey, which they capture in their bills. They swallow small fish whole while still underwater, but may take larger fish to the surface to eat. Like puffins, Razorbills can catch and hold several fish at once in their bills, when foraging for their nestlings.

Like many other marine birds, Razorbills breed in colonies. On average, nest sites are spaced less than 1 meter apart from each other. Nest sites are generally at least partially enclosed, on ledges or in crevices among rocks. Nests may be simple scrapes in soft ground, or may consist of seashells, pebbles, vegetation, and bones brought to the site. Established pairs often reuse nest sites from year to year.

Adult Razorbills do not breed until they are at least four to five years old. Male and female Razorbills have a strong pair bond and remain socially monogamous for life. Even so, sexual activity outside the pair bond (known among biologists as "extra-pair copulations") is relatively common. At a colony on Skomer Island off Wales, researchers observed that 32 of 33 females had received extra-pair copulation attempts. Apparently, however, such extra-pair attempts only rarely result in fertilization, in large part because paired Razorbills copulate very frequently — 80 times in 30 days, on average, at the same Skomer Island colony.

Breeding females invariably lay only one egg per clutch; in slightly more than half of cases when eggs are lost early in the breeding season, females lay one replacement egg. In contrast to the dramatically pointed eggs of some other cliff breeders, Razorbill eggs do not have particularly specialized shapes. Females and males split incubation duties equally, for a total of about 35 days before hatching.

Because newly hatched Razorbills cannot maintain their body temperatures on their own, they spend at least the first nine days of their lives almost constantly under the wing of one or the other parent. Parents generally feed nestlings three to four times daily, with one to four small fish per feeding.

When young Razorbills are ready to leave the nest, generally around 20 days after hatching, they bear complete body plumage, but no long flight feathers on their wings and tails. Their body mass is only about one-quarter that of mature adults. This "intermediate" developmental strategy is unique to the Razorbill and its two closest living relatives, Common and Thick-billed murres. Other species of birds fledge either very shortly after hatching, or conversely, after they have attained the size and key capabilities of adults.

Fledgling Razorbills leave their nests synchronously in large numbers, in the waning light of late evening. The chick steps out to the edge of the nest site, followed closely by its father. Both chick and father call loudly. The chick may retreat several times before finally jumping and gliding down to the sea, followed closely by its father. (Razorbills with nest sites close to sea level walk to the water, instead of jumping.) Upon reaching the water, parent and chick call, rejoin each other, and swim away.

Chicks are able to swim and dive well immediately upon reaching water; researchers monitored one parent-chick pair swimming about 8 kilometers in 6 hours immediately upon leaving the colony. The chick and its father then live together at sea, apart from other Razorbills, probably for about two months, until the young Razorbill can fly. The female remains at the nest site for approximately two weeks after the young bird fledges, then heads off to sea alone.

Description: Razorbills are alcids, members of a taxonomic family of diving seabirds that includes murres, puffins, and auklets. Razorbills have black upperparts and snow-white underparts. Length approximately 17 inches from bill tip to tail. In summer, adults show thin white lines on the trailing edge of their wings, on lores (between eyes and bill), and vertically across bill, near the tip. Their bills are deep (measuring almost 1 inch from top of upper mandible to bottom of lower mandible, near the tip), with flattened sides. Adults' bills also have one to three shallow vertical grooves near the tip, visible only at close range. Tail is relatively long and pointed in comparison with other alcids, giving Razorbill a highly streamlined look in flight. Legs and feet are black.

In fall and winter, adults have whitish markings running from behind their eyes down the sides of their heads. Loral line may be faint or absent in fall and winter. First-winter birds resemble fall-winter adults, but are smaller overall, with shallower bills that lack any white line or grooves.

Razorbills are silent at sea. At their breeding colonies, adult Razorbills issue distinctive, vibrant croaking and growling calls, with subtle differences for various contexts (alarm, attacking predators, inviting approach by chick, etc.).


Visit Shaw Creek Bird Supply and see our selection of Bird Houses, Bird Feeders, Hummingbird Feeders & Heated Bird Baths .

Copyright © 2003 Shaw Creek Bird Supply