BC Conservation Data Centre: Species Summary
Ptychoramphus aleuticus
Cassin's Auklet
| Scientific Name: | Ptychoramphus aleuticus (Pallas, 1811) | ||||||||||
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| English Name: | Cassin's Auklet | ||||||||||
| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Vertebrate Animal | ||||||||||
| Species Code: | B-CAAU | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G4 (Apr 2016) | ||||||||||
| Provincial Status: | S2B,S3N (Apr 2018) | ||||||||||
| BC List: | Red | ||||||||||
| Provincial FRPA list: | Y (Jun 2006) | ||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Special Concern (Nov 2014) | ||||||||||
| SARA Schedule: | 1 - Special Concern (May 2019) | ||||||||||
| General Status Canada: | 3 - Sensitive (2005) | ||||||||||
| Migratory Bird Convention Act: | Y | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Global Reproduction Comments: | Significant annual variation occurs in the timing of the breeding, even at a single site. Clutch size is 1. Incubation, by both sexes, lasts 37-42 days (average 38). Young are tended by both parents, fledge in 5-7 weeks (average 6). Sometimes double-brooded. Yearlings and 2-year-olds do not breed. Often in large colony (100,000s pairs, sometimes several thousand pairs/ha) | ||||||||||
| Global Ecology Comments: | Adult annual survival rate normally is between 0.8 and 0.9 (see Condor 94:1019-1021). Significant predators in various areas include arctic fox, rat, western gull. | ||||||||||
| Migration Characteristics: (Global / Provincial) | |||||||||||
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Nonmigrant: Local Migrant: Distant Migrant: Within Borders Migrant: |
Y / Y / N / na / |
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| Habitats: (Type / Subtype / Dependence) |
Grassland/Shrub / Shrub - Natural / Facultative - occasional use
Ocean / Marine Island / Obligate Ocean / Pelagic / Facultative - frequent use Ocean / Sheltered Waters - Marine / Facultative - occasional use Ocean / Subtidal Marine / Facultative - occasional use Rock/Sparsely Vegetated Rock / Cliff / Facultative - frequent use Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - frequent use Subterranean / Sub-soil / Obligate |
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| Global Habitat Comments: | Nonbreeding: mostly pelagic, less frequently along rocky seacoasts (AOU 1983). Nests on offshore islands, mostly in areas with low vegetation (also under trees in some areas (e.g., southeastern Alaska, Washington), on both flat and sloping terrain, sometimes several hundred m from coast (Johnsgard 1987). Nests in burrow dug in ground or under rock; sometimes among driftwood or debris; usually uses same site in successive years. See Spendelow and Patton (1988) for further details. | ||||||||||
| Food Habits: |
Invertivore: Adult, Immature
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| Global Food Habits Comments: | Dives from surface (maximum diving depth averaged 28 m at Quenn Charlotte Islands, British Columbia). Breeding season diet includes euphausiids, hyperiid amphipods, larval squids, crab megalops, copepods, various larval or small fishes (when invertebrates not readily available), and other invertebrates. Invertebrates 6-30 mm long, fishes 15-45 mm. See Johnsgard (1987.) | ||||||||||
| Global Phenology: |
Circadian: Adult, Immature
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| Global Phenology Comments: | Forages diurnally; feeds young at night (food stored in pouch) (Johnsgard 1987). | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
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| Colonial Breeder: | Y | ||||||||||
| Length(cm)/width(cm)/Weight(g): | 23/ / 188 | ||||||||||
| Elevation (m) (min / max): |
Global:
Provincial: |
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| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | BREEDS: locally on coastal islands from southern Alaska (Aleutian Islands) south to southern Baja California. Most (80%) of the population breeds along the coast of British Columbia. WINTERS: along the Pacific coast from southern British Columbia, rarely from southern Alaska, south to southern Baja California. One of the most abundant and widely distributed small alcids off the Pacific coast (Terres 1980). Casual in Washington and Oregon (AOU 1983). | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | HAMMERSON, G. | ||||||||||
| Last Updated: | Sep 05, 1995 | ||||||||||
| Provincial Information Author: | |||||||||||
| Last Updated: | |||||||||||
| References and Related Literature | |||||||||||
American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp. |
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Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, et al. 1990b. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC. |
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Forest Practices Code. 1997. Cassin's Auklet in Species and Plant Community Accounts for Identified Wildlife: Vol. 1. B.C. Minist. For. and B.C. Environ. 184pp. |
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Harfenist, A., K.R. MacDowell, T. Golumbia, G. Schultze, and Laskeek Bay Conservation Society. 2000. Monitoring and Control of Raccoons on Seabird Colonies in Haida Gwaii (Queen Charlotte Islands). Pp. 333-339 in L.M. Darling, ed. 2000. Proc. Conf. on the Biology and Manage. Species and Habitats at Risk, Kamloops, B.C., 15-19 Feb., 1999. Vol. 1; B.C. Minist. Environ., Lands and Parks, Victoria, BC, and Univ. College of the Cariboo, Kamloops, BC. 490pp. |
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Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio. |
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Hatch, S. A., and M. A. Hatch. 1990. Breeding seasons of oceanic birds in a subarctic colony. Can. J. Zool. 68:1664-1679. |
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Hyslop, C., and J. Kennedy, editors. 1992. Bird trends: a report on results of national ornithological surveys in Canada. Number 2, Autumn 1992. Migratory Birds Conservation Division, Canadian Wildlife Service, Ottawa, Ontario. 20 pp. |
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Johnsgard, P. A. 1987. Diving birds of North America. Univ. Nebraska Press, Lincoln. xii + 292 pp. |
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Lensink, C. J. 1984. The status and conservation of seabirds in Alaska. Pages 13-27 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Publ. No. 2. |
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Sealy, S. G., editor. 1990. Auks at sea. Western Foundation of Vertebrate Zoology, Studies in Avian Biology No. 14. vi + 180 pp. |
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Spendelow, J. A. and S. R. Patton. 1988. National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-1982. U.S. Fish and Wildlife Service, Biological Report 88(5). x + 326 pp. |
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Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York. |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. 1995. Species Summary: Ptychoramphus aleuticus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Oct 3, 2026).