Razorbill

For other uses, see Razorbill (disambiguation).

Razorbill
On Skomer Island, Pembrokeshire, Wales
Pair of Razorbills calling, recorded on Skokholm, Wales
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Alcidae
Genus: Alca
Species:
A. torda
Binomial name
Alca torda
Subspecies[3]
  • A. t. torda - Linnaeus, 1758
  • A. t. islandica - Brehm, CL, 1831

The razorbill, razor-billed auk,[4] or lesser auk[5] (Alca torda) is a North Atlantic colonial seabird and the only extant member of the genus Alca of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (Pinguinus impennis).[6]

Razorbills are primarily black with a white underside. The male and female are identical in plumage; however, males are generally larger than females. This agile bird, which is capable of both flight and diving, has a predominantly aquatic lifestyle and only comes to land in order to breed. It is monogamous, choosing one partner for life. Females lay one egg per year. Razorbills nest along coastal cliffs in enclosed or slightly exposed crevices. The parents spend equal amounts of time incubating, and once the chick has hatched, they take turns foraging for their young.

In 1918, the razorbill was protected in the United States by the Migratory Bird Treaty Act. Presently, this species faces major threats, including the destruction of breeding sites,[7] oil spills,[8] and deterioration of food quality. The IUCN records the population of the species as fluctuating,[1] causing its status to interchange. It has been recorded that the population had increased from 2008 to 2015,[9] decreased from 2015 to 2021,[10] and appears to be increasing or stable at the present.[1] It is estimated that the current global razorbill population lies between 838,000 to 1,600,000 individuals.[1]

  1. ^ a b c d BirdLife International (17 August 2021). "Alca torda (Razorbill)". IUCN Red List of Threatened Species. 17 August 2021: e.T22694852A228697220. doi:10.2305/IUCN.UK.2021-3.RLTS.T22694852A228697220.en. Retrieved 18 April 2024.
  2. ^ BirdLife International (18 December 2020). "Alca torda (Razorbill)". IUCN Red List of Threatened Species. 18 December 2020: e.T22694852A166289520. doi:10.2305/IUCN.UK.2021-3.RLTS.T22694852A166289520.en. Retrieved 18 April 2024.
  3. ^ Gill F, D Donsker & P Rasmussen (Eds). 2020. IOC World Bird List (v10.2). doi : 10.14344/IOC.ML.10.2.
  4. ^ American Ornithologists' Union (1931), A Check-List of North American Birds (4th ed.), Lancaster, PA: Lancaster Press, p. 144
  5. ^ Proceedings of the Society of Antiquaries of Scotland, Volume 13 (Edinburgh: Society of Antiquaries of Scotland, 1879), ISBN 9781248434567
  6. ^ Moum, Truls; Arnason, Ulfur; Árnason, Einar (2002). "Mitochondrial DNA sequence evolution and phylogeny of the Atlantic Alcidae, including the extinct Great Auk (Pinguinus impennis)". Molecular Biology and Evolution. 19 (9). Oxford: Oxford University Press: 1434–1439. doi:10.1093/oxfordjournals.molbev.a004206. PMID 12200471.
  7. ^ Lavers, Jennifer; Hipfner, J. Mark; Chapdelaine, Gilles (28 October 2009). "Razorbill - Introduction - Birds of North America Online". birdsna.org. doi:10.2173/bow.razorb.01. S2CID 216173366. Retrieved 6 September 2018.
  8. ^ Leopold, Mardik (January 2004). "The Tricolor oil spill: Characteristics of seabirds found oiled in the Netherlands".
  9. ^ BirdLife International (1 May 2009). "Alca torda (Razorbill)". IUCN Red List of Threatened Species. 1 May 2009: e.T22694852A23088501. Archived from the original on 19 August 2023. Retrieved 18 April 2024.
  10. ^ BirdLife International (1 October 2015). "Alca torda (Razorbill)". IUCN Red List of Threatened Species. 1 October 2015: e.T22694852A82978388. doi:10.2305/IUCN.UK.2015-4.RLTS.T22694852A82978388.en. Archived from the original on 18 April 2024. Retrieved 18 April 2024.