Cook's petrel (Pterodroma cookii), or the tītī or blue-footed petrel,[2] is a Procellariform seabird. It is a member of the gadfly petrels and part of the subgenus Cookilaria Bonaparte, 1856, which includes the very similar Stejneger's petrel.

Cook's petrel
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Procellariidae
Genus: Pterodroma
Species:
P. cookii
Binomial name
Pterodroma cookii
(G.R. Gray, 1843)
Synonyms

Procellaria cookii G. R. Gray, 1843

Procellaria velox G. R. Gray, 1844 (nomen novum)

Pterodroma cookii orientalis Murphy, 1929

Morphology

edit
 
Cook's petrel mount from the collection of Auckland Museum

One of the smallest petrels, Cook's petrel is typically 25–30 cm (9.8–11.8 in) in length with a 65–66 cm (26–26 in) wingspan and a weight of around 200 g (7.1 oz). Its colouration is typical of gadfly petrels: pale grey upperparts with a dark grey "M" on the wings and white underparts.[3]

The bill is long and black with tubular nostrils on both sides. As in all members of the order Procellariiformes, this nostril configuration enables an exceptionally acute sense of smell, which the birds use to locate food and nest sites in the dark.

Diet

edit

Cook's petrel feeds mostly on fish and squid, with some crustaceans taken[citation needed]. The species is highly pelagic except when nesting.

Habitat

edit
 
Cook's petrel photographed in Hauraki Gulf, New Zealand

Cook's petrel breeds only in New Zealand on three small islands: Little Barrier Island, Great Barrier Island, and Codfish Island.[4] The breeding season is the southern summer, October–May.[3] It nests in burrows and rock crevices, preferring sites on thickly forested ridges. Its call is a three-part kek, kek, kek.[5] The species was formerly more numerous; the current population estimate is 1,258,000 and declining. It is classified as vulnerable because it breeds on only three small islands. While Little Barrier Island's population remains stable, the other two populations are decreasing. On Great Barrier Island, introduced pigs, dogs, rats and cats attack nests and burrows, as do native weka (a flightless rail), preying on eggs and nestlings and reducing the population from an estimated 20,000 to 100[citation needed]. Fossils show that prior to the arrival of humans to New Zealand, Cook's petrel used to breed on the mainland New Zealand North and South Islands.[4]

Cook's petrel migrates to the Pacific Ocean from New Zealand when it is not breeding. It has sometimes been seen off the west coast of the United States and off the west coast of tropical South America.

References

edit
  1. ^ BirdLife International (2018). "Pterodroma cookii". IUCN Red List of Threatened Species. 2018: e.T22697975A132616449. doi:10.2305/IUCN.UK.2018-2.RLTS.T22697975A132616449.en. Retrieved 13 November 2021.
  2. ^ "Cook's petrel | New Zealand Birds Online".
  3. ^ a b Robertson, Hugh; Barrie, Heather (1999). The Hand Guide to the Birds of New Zealand. Penguin. ISBN 978-0198508311.
  4. ^ a b Colin Miskelly; Dafna Gilad; Graeme Arthur Taylor; Alan Tennyson; Susan M. Waugh (2019). "A review of the distribution and size of gadfly petrel (Pterodroma spp.) colonies throughout New Zealand". Tuhinga: Records of the Museum of New Zealand Te Papa Tongarewa. 30. Te Papa: 99–177. ISSN 1173-4337. Wikidata Q106839633.
  5. ^ Harrison, P.; Perrow, M.; Larsson, H. (2021). Seabirds: The New Identification Guide. Lynx Edicions, Barcelona. 1-600 (400).
edit