Birds
Land birds found nowhere else, from a mockingbird with fewer than 400 left to a dove that survives only in zoos, and the boobies, frigatebirds and shearwaters that nest on the islands.
Background photo: Megan Applegate (Socorro)
Found nowhere else
Ashore on Socorro and Clarión, not from the boat
Four bird species and eleven subspecies are found only in the Revillagigedo Islands (UNESCO). Most live on Socorro, where feral cats and sheep have done great damage; the Socorro dove survives only in captivity (Wikipedia). Two small naval stations are the only settlements, so these birds are rarely seen by visiting divers (UNESCO). No photos yet on this page; each card links to photos online.
Key marks: Much stouter than other mockingbirds, built more like a thrasher. Young birds are more rufous above and heavily patterned below (Wikipedia).
Life: Fewer than 400 birds remain, all on Socorro, mostly in low forest above 600 m. Critically Endangered; feral cats, sheep and an introduced locust have all hit it (Wikipedia).
Key marks: A long-legged ground dove, 26.5–34 cm. Males have a deep cinnamon head and underparts, a blue-grey nape and an iridescent pink patch on the neck (Wikipedia).
Life: Extinct in the wild: last seen on Socorro in 1972, mainly because of feral cats. It survives in zoos, and aviaries on Socorro were built for a return; sheep were removed from the island by 2010 (Wikipedia).
Key marks: A small brown wren of the dry scrub.
Life: Still one of the most common land birds on Socorro, mostly below about 600 m; Near Threatened (Wikipedia).
Key marks: The only wren on Clarión.
Life: Found only on Clarión Island; listed as Vulnerable (Wikipedia).
Seabirds
Seen from the boat and on the rocks
Key marks: A small shearwater, dark above and white below, flying low over the water on stiff wings.
At Socorro: Breeds only around Cerro Evermann on Socorro, with 249–999 mature birds; gone from San Benedicto and Clarión. Critically Endangered, mainly because of feral cats (Wikipedia).
Key marks: White, with a black face mask, black flight feathers and a black tail, and a yellowish bill.
At Socorro: Seen resting on the rocks at San Benedicto between dives (trip report 2001).
Key marks: Dark chocolate-brown head, breast and upperparts, sharply divided from a white belly; yellowish bill and feet.
At Socorro: Breeds on San Benedicto, its northernmost colony (Wikipedia); seen on the rocks there between dives (trip report 2001).
Key marks: Bright blue feet, brown wings and back, and a pale, finely streaked head.
At Socorro: A colony on San Benedicto, between Herrera and Bárcena, possibly its northernmost (Wikipedia).
Key marks: White, with a red bill, a black stripe through the eye, fine black barring on the back and very long white tail streamers.
At Socorro: Breeds on San Benedicto (Wikipedia).
Key marks: A large, slim shearwater with a long, wedge-shaped tail, usually dark brown, flying low and buoyantly over the waves.
At Socorro: Breeds on San Benedicto, its easternmost colony (Wikipedia).
Credits
Photos and their sources
These photos were taken elsewhere and show what each species looks like.
| Species | Photographer | Licence | Source |
|---|---|---|---|
| Nazca booby | Benjamint444 | GFDL 1.2 | Wikimedia Commons |
| Red-footed booby | Pacific Rim Conservation, photographer not named | © Pacific Rim Conservation, no open licence stated | pacificrimconservation.org |
| Great frigatebird | Charles J. Sharp | CC BY-SA 3.0 | Wikimedia Commons |
| Red-billed tropicbird | Unknown author | CC0 | Wikimedia Commons |