Birdfinding.info ⇒ Locally common around its nesting islands and seasonally in the remote waters south of New Zealand and Tasmania and in the Bering Sea and adjacent North Pacific. Regularly found on pelagic trips out of Eaglehawk Neck, Tasmania, and Stewart Island, New Zealand. Regular throughout Hawaiian waters during migration periods—mostly April-May and October to December—when it is often seen on pelagic trips out of Kailua-Kona and Honolulu, and west of Kauai in the Kaulakahi Channel. It is sometimes seen south of the Alaska Peninsula along the Dutch Harbor ferry route, and less often from the ferry to Kodiak. Also regular but rare, mainly October to December, in offshore waters from British Columbia to California.
Mottled Petrel
Pterodroma inexpectata
Breeds on New Zealand’s southern islands, and ranges from the Southern Ocean north to the Bering Sea.
Breeding. Breeds colonially from October to May, nesting in burrows on several island groups of southern New Zealand: mainly on the Snares, Codfish, and Big South Cape Island—about 10,000 pairs on each—with smaller numbers on islets adjacent to Stewart Island and the Fiordland region of South Island, including an island in Lake Hauroko.
During the breeding season, it forages over a wide portion of the subantarctic waters of the Southern Ocean, south to around 65-70° South latitude.
Formerly nested in the interiors of both North and South Island, but extirpated by mammalian predators such as rats that accompanied the European colonists.
Nonbreeding. From May to October, most of the population winters in the Bering Sea and North Pacific from the Aleutians to the Gulf of Alaska.
Passage across the temperate and tropical latitudes is mainly through the central Pacific and occurs over fairly compressed periods: northbound in April-May, and southbound from October to December.
Some portion of the population (presumably immatures) apparently remains in the North Pacific year-round—or lingers longer in the northeastern Pacific before returning to New Zealand waters.
Identification
A robust, mid-sized gadfly petrel with distinctive gray underparts and boldly patterned black-and-white underwings.
Mottled Petrel, dorsal view showing typical “M” pattern. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 10, 2019.) © Paul Brooks
The upperparts are medium-gray overall and typically show a pronounced “M” pattern with dark bars the full length of the wing connected by a dark bar on the lower back, and distinctly pale-gray trailing edges on the secondaries and inner primaries.
The rump and tail are pale-gray. The head and neck usually appear slightly darker-gray than the back—with blackish shadows around the eyes.
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 10, 2019.) © Paul Brooks
Mottled Petrel, molting its flight feathers. (Bering Sea west of St. Matthew Island, Russia; July 11, 2013.) © Yuri Artukhin
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; November 29, 2019.) © Jan Andersson
Mottled Petrel. (Offshore from Lincoln City, Oregon; December 1, 2017.) © Christian Schwarz
Mottled Petrel. (Offshore from Lincoln City, Oregon; December 1, 2017.) © Ryan Shaw
Mottled Petrel. (Offshore from the Snares Islands, New Zealand; February 11, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; January 4, 2019.) © Koel Ko
Mottled Petrel, dorsal view showing typical “M” pattern. (Offshore from the Snares Islands, New Zealand; February 11, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (Offshore from Kailua-Kona, Big Island, Hawaii; March 24, 2019.) © Jacob Drucker
Mottled Petrel. (Bering Sea west of St. Matthew Island, Russia; July 11, 2013.) © Yuri Artukhin
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; March 1, 2019.) © James Bailey
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 21, 2020.) © Paul Brooks
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; November 29, 2019.) © Jan Andersson
Mottled Petrel. (Offshore from Kekaha, Kauai, Hawaii; April 6, 2019.) © Chris Benesh
The underparts are unique among Pterodroma petrels: mostly medium-gray on the chest and belly with white throat, lower belly, and undertail coverts. The shade and extent of gray vary and the boundary between gray and white is noticeably blotchy and irregular.
The underwings are mostly white with a thick black carpal bar on the leading edge and very thin dark trailing edge.
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 17, 2017.) © Malcolm Graham
Mottled Petrel. (South of New Zealand; February 28, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (Offshore from Kailua-Kona, Big Island, Hawaii; October 19, 2011.) © Daniel Webster / Cascadia Research Collective
Mottled Petrel. (Offshore from the Snares Islands, New Zealand; February 11, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (South of Nihoa, Hawaii; March 31, 2020.) © Eric VanderWerf
Mottled Petrel. (East of Pearl & Hermes Reefs, Hawaii; April 8, 2018.) © Eric VanderWerf
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 17, 2018.) © Paul Brooks
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; February 3, 2018.) © Robert Hamilton
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; January 4, 2019.) © Koel Ko
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; March 1, 2019.) © James Bailey
Mottled Petrel. (Offshore from Campbell Island, New Zealand; March 4, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; January 4, 2019.) © Koel Ko
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 21, 2020.) © Peter Vaughan
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 18, 2017.) © Paul Brooks
Mottled Petrel. (Offshore from the Snares Islands, New Zealand; February 11, 2019.) © Hiroyuki & Shoko Tanoi
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; November 21, 2020.) © Scott Linnane
Mottled Petrel. (Offshore from Kailua-Kona, Big Island, Hawaii; October 30, 2009.) © Daniel Webster / Cascadia Research Collective
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; November 29, 2019.) © Jan Andersson
Mottled Petrel. (Offshore from Eaglehawk Neck, Tasmania, Australia; February 3, 2018.) © Paul Brooks
Mottled Petrel, molting its flight feathers. (Bering Sea west of St. Matthew Island, Russia; July 11, 2013.) © Yuri Artukhin
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; March 1, 2019.) © James Bailey
Mottled Petrel. (Offshore east of Stewart Island, New Zealand; November 29, 2019.) © Jan Andersson
Mottled Petrel. (Snares Islands, New Zealand; April 29, 2009.) © Storm Petrel
Mottled Petrel. (Anchor Island, Dusky Sound, New Zealand; November 17, 2016.) © Jean-Claude Stahl
Mottled Petrel, adult and nestling. (North Promontory, Snares Islands, New Zealand; February 1986.) © Alan Tennyson
Mottled Petrel. (Station Cove, North East Island, Snares Islands, New Zealand; November 12, 2003.) © Thomas Mattern
Mottled Petrel. (Observation Rock, Snares Islands, New Zealand; February 1986.) © Alan Tennyson
Mottled Petrel. (Putauhinu Island, Stewart Island, New Zealand; March 2011.) © Colin Miskelly
Cf. Collared Petrel. Mottled and Collared Petrels occur together mostly during brief periods of Mottled’s north- and southbound migrations through the tropical Pacific. They are potentially confused with one another because their upperparts and underwings are generally similar and the darkest Collared Petrels can show mostly medium gray underparts—a feature that is otherwise unique to Mottled. The main difference is that Collared’s underparts are generally darkest around the collar and chest, then become progressively paler toward the tail, whereas the gray on Mottled’s underparts has a blotchy boundary and is usually paler on the chest and darker on the belly. Collared also differs in being smaller and thinner, and has more extensive dark trailing edges on its underwings than Mottled.
Notes
Monotypic species.
IUCN Red List Status: Near Threatened.
References
Alderfer, J., and J.L. Dunn. 2014. National Geographic Complete Birds of North America (Second Edition). National Geographic Society, Washington, D.C.
BirdLife International. 2018. Pterodroma inexpectata. The IUCN Red List of Threatened Species 2018: e.T22697963A132615071. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22697963A132615071.en. (Accessed January 15, 2021.)
Brazil, M. 2009. Birds of East Asia. Princeton University Press.
Brooke, M. 2004. Albatrosses and Petrels across the World. Oxford University Press.
eBird. 2021. eBird: An online database of bird distribution and abundance. Cornell Lab of Ornithology, Ithaca, N.Y. http://www.ebird.org. (Accessed January 15, 2021.)
Harrison, P. 1983. Seabirds: An Identification Guide. Houghton Mifflin, Boston.
Howell, S.N.G. 2012. Petrels, Albatrosses & Storm-Petrels of North America. Princeton University Press.
Howell, S.N.G., and K. Zufelt. 2019. Oceanic Birds of the World. Princeton University Press.
Onley, D., and P. Scofield. 2007. Albatrosses, Petrels & Shearwaters of the World. Princeton University Press.
Pratt, H.D., P.L. Bruner, and D.G. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press.
Pyle, R.L., and P. Pyle. 2017. The Birds of the Hawaiian Islands: Occurrence, History, Distribution, and Status. Version 2 (January 1, 2017). http://hbs.bishopmuseum.org/birds/rlp-monograph/. B.P. Bishop Museum, Honolulu, Hawaii.
Sagar, P.M. 2013. Mottled petrel. In New Zealand Birds Online (Miskelly, C.M., ed.). http://www.nzbirdsonline.org.nz/species/mottled-petrel. (Accessed January 15, 2021.)
Seabirding of Japan. 2021. Mottled Petrel. http://seabirding-japan.com/mottled-petrel/. (Accessed January 15, 2021.)
Sibley, D.A. 2000. The Sibley Guide to Birds. Alfred A. Knopf. New York.
Xeno-Canto. 2021. Mottled Petrel – Pterodroma inexpectata. https://www.xeno-canto.org/species/Pterodroma-inexpectata. (Accessed January 15, 2021.)