{{Short description|Species of bird}} {{Use New Zealand English|date=September 2025}} {{speciesbox |image = Cook's Petrel 0A2A7458.jpg | status = VU | status_system = IUCN3.1 | status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=BirdLife International |date=2018 |title=''Pterodroma cookii'' |volume=2018 |article-number=e.T22697975A132616449 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22697975A132616449.en |access-date=13 November 2021}}</ref> | genus = Pterodroma | species = cookii | authority = (G.R. Gray, 1843)
| range_map = Pterodroma cookii map.svg | synonyms = ''Procellaria cookii'' <small>G. R. Gray, 1843</small>
''Procellaria velox'' <small>G. R. Gray, 1844 (''nomen novum'')</small>
''Pterodroma cookii orientalis'' <small>Murphy, 1929</small>
}}
'''Cook's petrel''' ('''''Pterodroma cookii''''') or '''tītī''' (Māori), '''blue-footed petrel''', is a Procellariiform seabird endemic to New Zealand.<ref name=":1">{{cite web |title=Cook's petrel {{!}} New Zealand Birds Online |url=http://nzbirdsonline.org.nz/species/cooks-petrel}}</ref> It is a member of the gadfly petrels and part of the subgenus ''Cookilaria'' Bonaparte, 1856, which includes the very similar Stejneger's petrel.
==Morphology== [[File:Pterodroma cookii (AM LB4167-1).jpg|alt=Cook's petrel mount from the collection of Auckland Museum|left|thumb|Cook's petrel mount from the collection of Auckland Museum]] One of the smallest petrels, Cook's petrel is typically {{convert|25|-|30|cm|in|abbr=on}} in length with a {{Convert|65|-|66|cm|in|abbr=on}} wingspan and a weight of around {{convert|200|g|oz|abbr=on}}. Its colouration is typical of gadfly petrels: pale grey upperparts with a dark grey "M" on the wings and white underparts.<ref name=handguide/>
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 == Cook's petrel feeds mostly on fish and squid, with some crustaceans taken{{Citation needed|date=November 2011}}. The species is highly pelagic except when nesting.
==Habitat== thumb|left|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.<ref name=":0">{{Cite Q|Q106839633}}</ref> The breeding season is the southern summer, October–May.<ref name="handguide" /> It nests in burrows and rock crevices, preferring sites on thickly forested ridges. Its call is a three-part ''kek, kek, kek.''<ref>Harrison, P.; Perrow, M.; Larsson, H. (2021). Seabirds: The New Identification Guide. Lynx Edicions, Barcelona. 1-600 (400).</ref> 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|date=November 2011}}. 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.<ref name=":0" />
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== {{Reflist|refs= <ref name=handguide>{{cite book |last1=Robertson |first1=Hugh |last2=Barrie |first2=Heather |title=The Hand Guide to the Birds of New Zealand |year=1999 |publisher=Penguin |isbn=978-0-19-850831-1}}</ref> }} {{refbegin}} * {{cite book |publisher=National Geographic |title=Field Guide to the Birds of North America |year=2002 |isbn=0-7922-6877-6}} * {{cite book |title=Seabirds, an Identification Guide |first=Peter |last=Harrison |year=1985 |publisher=Houghton Mifflin |isbn=0-395-60291-2}} * {{cite book |title=Handbook of the Birds of the World |date=1992 |volume=1 |editor-first=Josep |editor-last=del Hoyo |isbn=84-87334-10-5 |url-access=registration |url=https://archive.org/details/handbookofbirdso0001unse }} *{{cite book |last=Sibley |first=David Allen |author-link=David Allen Sibley |date=2000 |title=The Sibley Guide to Birds |location=New York |publisher=Knopf |page=[https://archive.org/details/sibleyguidetobir00sibl_0/page/483 483] |isbn=0-679-45122-6 |url-access=registration |url=https://archive.org/details/sibleyguidetobir00sibl_0/page/483 }} {{refend}}
==External links== {{Commons category|Pterodroma cookii}} {{Wikispecies|Pterodroma cookii}} * {{BirdLife|22697975|Pterodroma cookii}} * {{Avibase|name=Pterodroma cookii}} * {{InternetBirdCollection|cooks-petrel-pterodroma-cookii}} * {{VIREO|Cook's+petrel}} * {{IUCN_Map|22697975/132616449|Pterodroma cookii}} * {{Xeno-canto species|Pterodroma|cookii|Cook's petrel}}
{{Taxonbar|from=Q596787}}
Cook's petrel Category:Birds of New Zealand Category:Birds of the Cook Islands Cook's petrel Cook's petrel
{{Procellariiformes-stub}}