Species

Justification
This species has a small breeding range and population which nests at a small number of known locations. The presence of introduced predators on most known and potential breeding islands suggests that numbers are likely to be declining significantly. It consequently qualifies as Vulnerable.

Taxonomic source(s)
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Synonym(s)
Brachyramphus craveri Collar and Andrew (1988), Brachyramphus craveri Stotz et al. (1996), Brachyramphus craveri craveri Collar and Andrew (1988), Brachyramphus craveri craveri Stotz et al. (1996)

Identification
25 cm. Small, black-and-white alcid. Black upperparts, white below. Black partial collar extending on to sides of breast. Black on head extends just under bill. Partial white eye-ring. Long slim bill. Dusky grey underwing linings. Similar spp. Xantus's Murrelet S. hypoleucus lacks partial breast-band and black extending under bill, and has white underwing linings and shortish, stout bill. Voice Shrill whistle, sometimes given as series.

Distribution and population
Synthliboramphus craveri has an estimated c.5,000 breeding pairs, scattered throughout the Gulf of California, Mexico (Everett and Anderson 1991). It breeds on Islas Partida, Tiburón, San Jorge, San Esteban, Estanque, San Pedro Mártir, San Pedro Nolasco, San Francisco, Espíritu Santo and San Ildefonso, and possibly on the Pacific coast of Baja California, north to Islas San Benitos (DeWeese and Anderson 1976, Everett and Anderson 1991, Velarde and Anderson 1994, E. Velarde in litt. 1998). The population, with pre-breeders, is probably 15,000-20,000 birds (Gaston and Jones 1998), which is similar to an at-sea survey estimate of c.22,000 birds (Pitman et al. 1995). It winters in the Gulf of California and along coasts to south California, USA, and Sonora, Mexico, and possibly Guatemala (DeWeese and Anderson 1976, Tershy et al. 1993).

Population justification
The population is estimated to number 9,000-15,000 individuals, roughly equating to 6,000-10,000 mature individuals.

Trend justification
Population declines are suspected owing to the various threats acting on all populations.

Ecology
Two eggs are usually laid on bare rock or soft substrate at the end of a rock-cavity or crevice, but also in ground-burrows, under dense shrubs and boulders (DeWeese and Anderson 1976, Gaston and Jones 1998). Nesting success varies from 12-79%, but chick survival during the first month at sea is only 30-35% (DeWeese and Anderson 1976). It feeds mainly on larval fish, especially rockfish Sebastes, herring (Clupeidae) and lanternfish Benthosema panamense (DeWeese and Anderson 1976).

Threats
Cats and rats are probably the greatest threat, presumably predating both adults and nests on several breeding islands (DeWeese and Anderson 1976). Deer mice may also pose a threat on some islands. Oil spills from the tanker lane stretching from the Gulf of California to Puerto Libertad could threaten a large percentage of breeding adults. Pollution from offshore oil-wells or the Los Angeles oil-tanker lane could also affect non-breeding adults in the south California Bight (Velarde and Anderson 1994). Further threats are drowning in drift gill-nets, nest-site disturbance and possibly organochlorine pollution (Velarde and Anderson 1994).

Conservation actions underway
A management plan and implementation strategy for the Gulf of California Special Biosphere Reserve were detailed in 1994 (Velarde and Anderson 1994), and work began in 1999 (D. W. Anderson in litt. 1999). Introduced mammals have been eradicated from a number of islands that are current, past or potential breeding sites (B. Tershy in litt. 1999, Tershy et al. 2002, B. Tershy in litt. 2007, Aguire et al. in press). Instructive signs have been placed on many of the islands and there is a general move towards increasing enforcement of existing regulations. At the same time, human use of the islands is increasing, much of it unregulated (B. Tershy in litt. 1999). Other measures include the development of management plans for all known breeding islands, environmental education, the erection of warning signposts on islands and increased enforcement of existing regulations (B. Tershy in litt. 1999).

Conservation actions proposed
Eradicate introduced predators on other small islands. Monitor all islands for new mammalian introductions. Develop strategies to remove predators from larger islands. Ensure the full implementation of the management plan. Estimate population sizes with precision. Monitor key populations. Assess the impact of gill-net fisheries (Everett and Anderson 1991). Regulate tourism on Baja California islands (Velarde and Anderson 1994).

References
DeWeese, L. R.; Anderson, D. W. 1976. Distribution and breeding biology of Craveri's Murrelet. Transactions of the San Diego Society of Natural History 18: 155-168.

Everett, W. T.; Anderson, D. W. 1991. Status and conservation of the breeding seabirds on offshore Pacific islands of Baja California and the Gulf of California. In: Croxall, J.P. (ed.), Seabird status and conservation: a supplement, pp. 115-139. International Council for Bird Preservation, Cambridge, U.K.

Tershy, B. R.; van Gelder, E.; Breese, D. 1993. Relative abundance and seasonal distribution of seabirds in the Canal de Ballenas, Gulf of California. Condor 95: 458-464.

Velarde, E.; Anderson, D. W. 1994. Conservation and management of seabird islands in the Gulf of California: setbacks and successes. In: Nettleship, D.N.; Burger, J.; Gochfeld, M. (ed.), Seabirds on islands: threats, case studies and action plans, pp. 229-243. BirdLife International, Cambridge, UK.

Pitman, R. L.; Ballance, L. T.; Reilly, S.; Force, M. 1995. Distribution, movements, and population status of Craveri's Murrelet: implications for ecology and conservation. Pacific Seabirds 22: 41.

Gaston, A. J.; Jones, I. L. 1998. The Auks. Oxford University Press, Oxford.

Aguirre-Muñoz, A.; Croll, D. A.; Donlan, J.; Henry III, R. W.; Hermosillo, M. A.; Howald, G. R.; Keitt, B. S.; Luna-Mendoza, L.; Rodríguez-Malagón, M.; Salas-Flores, L. M.; Samaniego-Herrera, A.; Sanchez-Pacheco, J. A.; Sheppard, J.; Tershy, B. R. 2008. High-impact conservation: invasive mammal eradications from the islands of western Mexico. Ambio 37(2): 101-107.

Tershy, B. R.; Donlan, C. J.; Keitt, B. S.; Croll, D. A.; Sanchez, J. A.; Wood, B.; Hermosillo, M. A.; Howald, G. R.; Biavaschi, N. 2002. Island conservation in north-west Mexico: a conservation model integrating research, education and exotic mammal eradication. In: Veitch, C. R.; Clout, M. N. (ed.), Turning the tide: the eradication of invasive species, pp. 293-300. IUCN SSC Invasive Species Specialist Group, Gland, Switzerland and Cambridge, UK.

Further web sources of information
Audubon WatchList

View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Gilroy, J.

Contributors
Anderson, D., Tershy, B., Verlarde, E.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2013) Species factsheet: Synthliboramphus craveri. Downloaded from http://www.birdlife.org on 21/05/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/05/2013.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

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