The razorbill is a species of seabird that belongs to the alcid family. It is the only living species in the genus Alca. Its scientific name is Alca torda. So the genus species of the razorbill is Alca torda.
The razorbill is a black and white seabird with a large, heavy black bill. It breeds on coasts and islands in the northern Atlantic Ocean. Razorbills nest in colonies on cliff ledges and rocky crevices, laying one egg per year. They spend most of their lives at sea, only coming to land in order to breed. Razorbills feed on small fish, crustaceans and other marine invertebrates, catching prey by pursuit diving underwater. The global population is estimated at 1.4 million breeding pairs. The razorbill faces threats from oil spills, bycatch in fishing nets, climate change and predation from foxes, gulls and other animals. However, overall populations remain stable and the razorbill is classified as Least Concern on the IUCN Red List.
Physical Description
The razorbill is a medium-sized seabird measuring 38–43 cm in length with a wingspan of 60–73 cm and a weight of 600–800 g. It has a large head, short neck, compact body and short legs set far back on its body. Its plumage is black on the upperparts and white on the underparts. The head, neck, back, wings and tail are all black. The underside of the wings are also white. The razorbill has a thick black bill that is large and deep with a blunt tip and vertical white line near the tip. The eyes are small and positioned high on the sides of the head. During the breeding season, the bill turns a grayish color with some white. The legs and feet are bright red. The webbed feet help the razorbill swim on the water surface.
Male and female razorbills look identical. Immature birds have a more variable amount of white streaking on the head and neck. Chicks are covered in black down. They develop their adult plumage starting around 9 weeks old.
Distinctive Features
Some key identifying features of the razorbill include:
- Black and white coloring
- Large, heavy black bill with vertical white line
- Short legs set far back on body
- Red feet
- Upright stance when on land
The razorbill’s thick black bill makes it distinctive from other auks. It uses this large bill to catch fish, hold on to mates, defend nest sites and groom feathers. The white line on the bill may help razorbills recognize others of their own species. The red feet provide camouflage when the razorbill floats on the water with its feet uncovered. The legs are set far back on its body to provide propulsion for diving and swimming.
Distribution and Habitat
The razorbill has a circumpolar distribution in the northern Atlantic Ocean. Breeding populations are found at these locations:
- Eastern Canada, Newfoundland and Labrador
- Northeastern United States, Maine
- Greenland
- Iceland
- Northern Europe including the British Isles, Scandinavia, Baltic Sea
- Northern Russia
The total global population is estimated at 1.4 million breeding pairs. The largest populations are found in Iceland (780,000 pairs) and eastern Canada (250,000 pairs).
Location | Breeding Population |
---|---|
Iceland | 780,000 pairs |
Eastern Canada | 250,000 pairs |
Northeastern USA | 3,000 pairs |
Greenland | 100,000 pairs |
British Isles | 104,000 pairs |
Baltic Sea | 52,000 pairs |
Northern Russia | 100,000 pairs |
Razorbills spend the winter farther south into the Atlantic on both sides of the ocean. However, some birds may remain in northern latitudes year-round if food supplies persist.
During the breeding season, the razorbill nests in colonies along rocky cliffs, islands and promontories. Nest sites are often surrounded by sheer drops into the sea. Razorbills typically return to the same nesting site each year. They form large breeding colonies ranging from 50 to 75,000 pairs. Colonies are usually shared with other seabird species.
The rest of the year, razorbills live solitarily or in small flocks out at sea. They prefer coastal waters and continental shelves within 50 km of land. Razorbills winter as far south as New Jersey on the North American side, and France and Iberia on the European side of the Atlantic.
Diet and Feeding
The razorbill is a piscivore, feeding predominantly on small schooling fish. Capelin, sand lance, juvenile cod, sprats and herring make up the majority of its diet. Razorbills also sometimes eat crustaceans such as krill, amphipods and crabs, and other marine invertebrates.
Razorbills are pursuit divers, swimming underwater to catch prey. They can dive to depths over 120 m to find food, though most dives are within 30 m of the surface. The birds use their wings for propulsion and steer with their feet and tail to chase down fast-moving fish. They can swallow small fish whole underwater. Razorbills can continue hunting through dense schools of fish, ingesting up to 60 small fish in one diving bout.
Chicks are fed whole fish by the parents, first being given tiny fish such as sand lance or juvenile herring. Adults hold fish crosswise in their bills for the young to take.
Razorbills have a salt gland in their nasal passages that enables them to drink seawater and excrete excess salt. This allows them to remain at sea for extended periods without needing to find freshwater sources.
Life Cycle and Reproduction
Razorbills become sexually mature at ages 4-7. They choose a new mate each breeding season in elaborate pairing rituals. Thousands of razorbills will assemble at breeding colonies around nesting areas. Males and females perform billing ceremonies, touching bills and calling while upright with their feathers puffed out. This allows them to confirm pair bonds.
Paired razorbills defend nesting spots, usually simple depressions or crevices on bare rock cliffs. Breeding begins between mid-March and mid-June depending on latitude. The female lays a single egg that is pear-shaped and white to brownish with dark speckles. Parents take turns incubating the egg for around 5 weeks before it hatches. Razorbill eggs have an extremely high yolk to albumen ratio, allowing the chick to grow very quickly.
Once hatched, razorbill chicks are fed whole fish by both parents. Initially the young are brooded and guarded at the nest. Around 20-25 days old, the chicks will venture out onto nearby rocks, flapping their developing wings. They fledge at around 6 weeks old, jumping into the sea accompanied by the male parent who shows them how to feed. The female parent remains at the nesting ledge. By 9 weeks of age, young razorbills are proficient swimmers and divers, flying competently by 12 weeks old. Juveniles remain at sea 2-3 years before returning to breeding colonies.
Razorbills are long-lived for their size, surviving over 30 years in the wild. Annual adult survival rates are estimated at 91%. Razorbills face predation mainly from foxes, gulls, ravens, eagles and owls which may take eggs or chicks. Mink and rats can be problematic at some colonies. Adults are preyed on occasionally by large gulls and great skuas.
Migration
The razorbill is partially migratory, with northern breeding populations migrating south for the winter while more southern breeders tend to remain nearer to colony sites year-round. Fall migration begins shortly after breeding in late summer and early fall. Spring migration back to the breeding colonies occurs between late winter and early spring.
During the non-breeding season, razorbills undergo dispersal movements based on food availability rather than true migration. They tend to disperse southward and offshore from breeding areas. Some migration and wintering takes place among offshore banks and continental shelf areas where food is plentiful enough to sustain them through winter.
Migratory connectivity studies using razorbill band recoveries and geolocators have shown that birds exhibit differential migration rather than flying to a single wintering area. However, some general migratory tendencies have been noted:
- Canadian Arctic and Greenland birds migrate down Atlantic coast to New England and mid-Atlantic
- Northeastern U.S. breeders move offshore and south to mid-Atlantic
- Iceland populations move southward along coasts to waters from southern Greenland to Portugal
- UK breeders shift from North and Irish Seas to Bay of Biscay and Iberian coasts
Razorbills mostly migrate solo or in small groups, not in large concentrated flocks like some seabird species. Migration routes generally follow coastlines, while wintering ranges expand further offshore into pelagic waters.
Threats and Conservation
The global population of razorbills is currently estimated at 1.4 million breeding pairs and is considered stable. However, razorbills face a variety of threats on both breeding and wintering grounds:
- Oil spills – Razorbills suffer from the impacts of oil spills which can destroy feather waterproofing and lead to hypothermia and ingestion of toxins.
- Incidental bycatch – Razorbills are vulnerable to drowning after being caught on longlines and in fishing nets.
- Overfishing – Reduction of fish stocks such as sand lance and capelin may impact their food supply.
- Predators – Terrestrial predators including foxes, rats, mink and gulls rob nests and take eggs and chicks.
- Disturbance – Human activities near breeding colonies can displace nesting birds.
- Climate change – Warming ocean temperatures may shift prey distributions and impact breeding success.
Some protective measures for razorbills include:
- Establishing marine protected areas around breeding colonies
- Regulations on offshore oil and gas exploration
- Using bird deterrents on fishing gear to minimize bycatch
- Control of invasive mammalian predators at nesting sites
- Monitoring and restrictions on human activity near breeding cliffs
Due to its large global population and range, the razorbill is currently classified as Least Concern on the IUCN Red List of Threatened Species. However, some regional populations such as in the Baltic Sea are declining. Continued monitoring and conservation will be important for this iconic seabird.
Razorbill populations can serve as indicators of the overall health of the marine ecosystems they depend on.
Conclusion
In summary, the razorbill is the sole living species in the Alca genus, with the scientific name Alca torda. It is a black and white auk breeding in northern Atlantic colonies and wintering widely across pelagic waters. Razorbills nest on rocky cliffs and shores, feeding on fish caught by pursuit diving. They have a large global population but face threats from oil pollution, fisheries bycatch, climate change and disturbance. Maintaining healthy oceans and managing human activities will be key to ensuring the long-term survival of these robust seabirds.