Ashy Storm-petrel (Oceanodroma homochroa)
The Ashy Storm-Petrel is medium in size, smoke gray-brown all over, and with primaries darker than other feathers. Chicks hatch completely covered in a thick layer of pale gray down, remaining virtually indistinguishable from chicks of other nesting storm-petrels in North America. Newly fledged individuals exhibit scapulars and wing-coverts edged with light, pearly gray. At sea, size differences and tail shapes are difficult to discern, and apparent color varies with light conditions. Under these conditions, the Ashy Storm-Petrel is best recognized by flight action: except when taking off from the water, it raises its wings only to about the horizontal before each downstroke; other storm-petrels in its range raise their wings much higher.
References for Species Profile
- Ainley, David. 1995. Ashy Storm-Petrel (Oceanodroma homochroa), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/185
- Ainley, D. G. and T. J. Lewis. 1974. The history of Farallon Island marine bird populations, 1854-1972. Condor 76:432-446.
- Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford Univ. Press, Oxford.
- Shuford, W. D., and Gardali, T., editors. 2008. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento.
- Stallcup, R. 1990. Ocean birds of the nearshore Pacific. Point Reyes Bird Observ. Stinson Beach, CA.
- Sydeman, W.J., N. Nur, E.B. McLaren, and G.J McChesney. 1998. Status and trends of the Ashy Storm-Petrel on Southeast Farallon Island, California based on capture-recapture analysis. Condor 438-447.
- States/US Territories in which the Ashy Storm-petrel, Wherever found is known to or is believed to occur: California
- US Counties in which the Ashy Storm-petrel, Wherever found is known to or is believed to occur: View All
Status Date Listed Lead Region Where Listed Pacific Region (Region 1) Wherever found
» Federal Register Documents
Date Citation Page Title 08/19/2009 74 FR 41832 41860 12-Month Finding on a Petition To List the Ashy Storm-Petrel as Threatened or Endangered 11/15/1994 59 FR 58982 59028 ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species. 10/22/2013 78 FR 62523 62529 12-Month Finding on a Petition To List Ashy Storm-Petrel as an Endangered or Threatened Species 05/15/2008 73 FR 28080 28084 90-Day Finding on a Petition To List the Ashy Storm-Petrel (Oceanodroma homochroa) as Threatened or Endangered 11/28/2012 77 FR 70987 70988 Status Review for a Petition To List the Ashy Storm-Petrel as Endangered or Threatened: Notice; initiation of status review and solicitation of new information.
No recovery information is available for the Ashy Storm-petrel.
» Critical Habitat
No critical habitat rules have been published for the Ashy Storm-petrel.
» Conservation Plans
No conservation plans have been created for Ashy Storm-petrel.
» Life History
Breeding habitat requires rocky islands among talus slopes. Ashy Storm-Petrels spend most of their time at sea, however, and only visit land to court and tend to chicks. They avoid neritic waters overlying the continental shelf, but frequent those along the continental slope. Nests occur in natural cavities, mostly in talus but also in hard rock. They are placed on drier portions of islands where vegetation isn't dense, as to inhibit entry of talus crevices.
Diet is not well known, but likely includes prey species of the sea-surface/air interface including small fish, young squid and crustaceans. If the prey item is large, food is obtained by sitting on the water and tearing pieces of with their bill. Ashy Storm-Petrels are known to scavenge, as they are attracted to fishing vessels and fish-oil slicks. Feeding takes place mostly at night or during crepuscular periods.
Movement / Home Range
The Ashy Storm-Petrel occurs year-round in waters of the continental slope and slightly farther to sea from Cape Mendocino, CA and south the northern Baja California, Mexico. During spring and summer, the Ashy Storm-Petrel concentrates in the vicinity of the Farallon and Channel Islands and the counties of San Francisco and Santa Barbara. Notes on population size at the Farallon Islands have been made periodically since the mid-1880s, but recent historical data are unavailable for other nesting sites. Little indication of population change was apparent through the early 1970s. A study in the early 1990s (Sydeman et al 1998) indicated an overall population decline of 34% since the 1970s in the Farallon Island, suggesting the need for protections and conservation action.
The biggest conservation concerns for the Ashy Storm-Petrel are degradation of habitat, disturbance at nest sites, and ingestions of plastics. For more information about this species, refer to the following resource:
- Shuford, W. D., and Gardali, T., editors. 2008. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=10386
» Other Resources
NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.