Striated caracara

The striated caracara or Forster's caracara (Phalcoboenus australis) is a Near Threatened bird of prey of the family Falconidae, the falcons and caracaras.[4][1] It is found in Argentina, Chile, and the Falkland Islands.[5] In the Falklands it is known as the Johnny rook, probably named after the Johnny penguin (gentoo penguin).[6]

Striated caracara
CITES Appendix II (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Falconiformes
Family: Falconidae
Genus: Phalcoboenus
Species:
P. australis
Binomial name
Phalcoboenus australis
(Gmelin, JF, 1788)
Synonyms

Daptrius australis[3]

Taxonomy and systematics

The striated caracara was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the falcons and eagles in the genus Falco and coined the binomial name Falco australis.[7][8] The specific epithet australis is Latin meaning "southern".[9] Gmelin based his description on the "Statenland eagle" that had been described in 1781 by the English ornithologist John Latham in his A General Synopsis of Birds. Latham had obtained notes on the bird from the naturalist Johann Reinhold Forster.[10] Johann Forster and his son Georg Forster had accompanied James Cook on his second voyage to the Pacific Ocean. The son Georg made a water-colour drawing of the striated caracara during their visit to Staten Island (east of Tierra del Fuego). The drawing is dated 3 January 1775 and is now held by the Natural History Museum in London.[11] The striated caracara is now one of four species placed in the genus Phalcoboenus that was introduced in 1834 by Alcide d'Orbigny.[12]

The taxonomy of the caracaras has not been settled. The American Ornithological Society and the International Ornithological Committee place the striated and three other caracaras in genus Phalcoboenus.[13][12] BirdLife International's Handbook of the Birds of the World also places the striated caracara in Phalcoboenus, and includes four other caracaras.[14] The Clements taxonomy places the striated and six other caracaras in genus Daptrius.[15][3]

The taxonomic systems agree that the striated caracara is monotypic.[12][14][3]

Description
Watercolour made by Georg Forster in 1775 on James Cook's second voyage to the Pacific Ocean.

The striated caracara is 53 to 65 cm (21 to 26 in) long with a wingspan of 116 to 125 cm (46 to 49 in), and weighs about 1.2 kg (2.6 lb). The sexes' plumages are alike. Adults are mostly black to brownish back with white or tawny streaks on the upper back, neck, and breast. Their tail has a wide white tip, their underwing coverts and thighs are bright rusty rufous, and their primaries have white bases. The bare skin on their face is salmon pink to yellowish orange, their iris brown, and their legs and feet bright orange-yellow. Juveniles are black to brownish black with a chestnut tail and gray bare parts; they gradually attain adult plumage and bare skin colors over their first five years.[4][16]

The most common calls are "a cat-like wailing waa-aow, a high-pitched, repeated scream, a loud cawing kaa in face of human intruders, and short sharp clicks around the nest."[16]

Distribution and habitat

The striated caracara is found on the outer Falkland Islands, Isla Grande de Tierra del Fuego, Isla de los Estados (Staten Island), Isla Navarino, Cape Horn, and other islands in the far south of Argentina and Chile. It was hunted to extirpation on East Falkland. It primarily inhabits rocky coasts with adjacent tussock grass but also ranges inland to mountain foothills up to about 500 m (1,600 ft) above sea level.[4][16] It is generally non-migratory but may move seasonally to higher elevations. It also may be only a winter visitor to some of the South American islands.[4][16]

Behavior

Feeding

The striated caracara is an opportunist species, feeding on everything from carrion, seabirds, marine mammals, invertebrates, stolen eggs, livestock, and food scraps around human settlements.[17] Recorded prey species include penguin adults and chicks,[18] brown skua,[19] seal pups such as the South American fur seal and Southern elephant seal, blackish cinclodes, various shellfish, and eggs from nesting seabirds including penguins, cormorants; among many other species.[20] Most predation of larger species is usually done in small groups, where they together mob the larger animal. Invertebrates are also part of their diet, including kelp fly larvae dug from intertidal kelp wrack, beetles, mussels, limpets, and earthworms dug from invasive grasses in hillside drainages. They also have been recorded predating young lambs, which led to persecution by sheep farmers before a 1999 law forbid killing the species.[21] Striated caracaras are also parasitic, displacing and robbing scavengers and small groups will attack healthy birds as large as kelp geese (Chloephaga hybrida).[4][16] A population of striated caracaras on New Island was found to largely subsist on live slender-billed prions (both and older birds), which were hunted in the open or taken from nest burrows.[22]

Breeding

On the Falkland Islands the striated caracara breeds between late October and January. Its nest is built of twigs and grass on the ground, under tussoc grass clumps, or on cliff ledges. It usually nests in loose colonies with nests sometimes as little as 7 m (20 ft) apart, and there is some evidence of cooperative breeding. The clutch size is usually two eggs but can be up to four. The incubation period, time to fledging, and details of parental care are not known.[4][16]

Status

The IUCN has assessed the striated caracara as Near Threatened. It has a very limited range and an estimated population of under 2,500 mature individuals, though the latter is believed to be stable. The predicted ecosystem stresses of climate change are the only known significant threat.[1] The breeding population on the Falklands in 2006 was about 500 pairs, and 350 to 450 pairs may also be on the South American islands.[16]

  • Subadult striated caracara feeding on a dead gentoo penguin chick
    Subadult striated caracara feeding on a dead gentoo penguin chick
  • Juvenile (2 year old) striated caracara
    Juvenile (2 year old) striated caracara
  • Subadult striated caracara at Amazona Zoo, Norfolk, England
    Subadult striated caracara at Amazona Zoo, Norfolk, England
  • Adult striated caracaras on Sea Lion Island, Falkland Islands
    Adult striated caracaras on Sea Lion Island, Falkland Islands

References
  1. BirdLife International (2016). "Striated Caracara Phalcoboenus australis". IUCN Red List of Threatened Species. 2016: e.T22696247A93551504. doi:10.2305/IUCN.UK.2016-3.RLTS.T22696247A93551504.en. Retrieved 15 February 2023.
  2. "Appendices | CITES". cites.org. Retrieved February 13, 2023.
  3. Clements, J. F., T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements checklist of birds of the world: v2022. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ retrieved November 10, 2022
  4. Ferguson-Lees, James; Christie, David A. (2001). Raptors of the World. New York: Houghton Mifflin. pp. 802–803. ISBN 0-618-12762-3.
  5. Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. 30 January 2023. Species Lists of Birds for South American Countries and Territories. https://www.museum.lsu.edu/~Remsen/SACCCountryLists.htm retrieved January 30, 2023
  6. Gorman, James (1990). The Total Penguin. Prentice Hall. p. 87. ISBN 978-0-13-925041-5. Sealers called it the "Johnny penguin" or "John penguin." In that incarnation, it seems to have given its name to the striated caracara, a bird of prey that feeds on young gentoo penguins in the Falklands and is called the "Johnny rook."
  7. Gmelin, Johann Friedrich (1788). Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1, Part 1 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 259.
  8. Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-List of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 392.
  9. Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 62. ISBN 978-1-4081-2501-4.
  10. Latham, John (1781). A General Synopsis of Birds. Vol. 1, Part 1. London: Printed for Leigh and Sotheby. pp. 40–41.
  11. Lysaght, Averil (1959). "Some eighteenth century bird paintings in the library of Sir Joseph Banks (1743-1820)". Bulletin of the British Museum (Natural History), Historical Series. 1 (6): 251-371 [281, No. 34].
  12. Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (January 2023). "Seriemas, falcons". IOC World Bird List Version 13.1. International Ornithologists' Union. Retrieved 19 February 2023.
  13. Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 30 January 2023. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved January 30, 2023
  14. HBW and BirdLife International (2022) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 7. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v7_Dec22.zip retrieved December 13, 2022
  15. Fuchs, Jérôme; Johnson, Jeff A.; Mindell, David P. (2012). "Molecular systematics of the caracaras and allies (Falconidae: Polyborinae) inferred from mitochondrial and nuclear sequence data". Ibis. Wiley. 154 (3): 520–532. doi:10.1111/j.1474-919x.2012.01222.x.
  16. Bierregaard, R. O., G. M. Kirwan, E. F. J. Garcia, and J. S. Marks (2022). Striated Caracara (Daptrius australis), version 1.1. In Birds of the World (N. D. Sly, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.strcar1.01.1 retrieved February 15, 2023
  17. "Striated Caracara".
  18. "Attempted Predation of Striated Caracara on Gentoo Penguin".
  19. "Demography and breeding success of Falklands skua at Sea Lion Island, Falkland Islands" (PDF).
  20. "Caracara: variable diet".
  21. "Striated Caracara Phalcoboenus australis".
  22. Catryfirst1=P.; Lecoq, M.; Strange, I.J. (2008). "Population growth and density, diet". Polar Biology. 31: 1167–1174. doi:10.1007/s00300-008-0454-8.

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