Ptychoramphus aleuticus

East North Pacific

Cassin's Auklet ranges from Baja California (Mexico) up the Pacific coast of the USA and Canada, through Alaska to the Aleutian Islands (USA)¹.

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) 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).

Length: 23 cm

Weight: 188 grams

Habitat and Ecology

Systems

• Terrestrial
• Marine

Depth range based on 13641 specimens in 1 taxon.
Water temperature and chemistry ranges based on 6997 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): 10.712 - 17.806
  Nitrate (umol/L): 0.071 - 4.675
  Salinity (PPS): 30.381 - 33.573
  Oxygen (ml/l): 5.473 - 6.587
  Phosphate (umol/l): 0.330 - 0.800
  Silicate (umol/l): 1.436 - 16.169

Graphical representation

Temperature range (°C): 10.712 - 17.806

Nitrate (umol/L): 0.071 - 4.675

Salinity (PPS): 30.381 - 33.573

Oxygen (ml/l): 5.473 - 6.587

Phosphate (umol/l): 0.330 - 0.800

Silicate (umol/l): 1.436 - 16.169
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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.)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 - 300

Comments: Sixty-six colonies with more than 500 breeding birds are listed in Manuwal and Thoresen (1993). An estimated 70-80 colonies exist in British Columbia alone (British Columbia Conservation Data Centre).

>1,000,000 individuals

Comments: Total population has been estimated to be 3,568,000 breeding individuals (Manuwal and Thoresen 1993). British Columbia population was estimated at 2.7 million breeding birds in the early 1990s, representing 80% of the estimated world population (Kaiser, in Hyslop and Kennedy 1992).

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.

Comments: Forages diurnally; feeds young at night (food stored in pouch) (Johnsgard 1987).

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)

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 2 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 8
Species With Barcodes: 1

Canada

Rounded National Status Rank: N2B - Imperiled

United States

Rounded National Status Rank: N4 - Apparently Secure

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Least Concern

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Abundant and widespread breeder, but has declined significantly from past numbers. Much of the population is concentrated in a few colonies off the British Columbia coast. Large colonies may be extirpated when predatory mammals are introduced. Remaining colonies are still vulnerable to introduction of rats, raccoons and foxes. Oil spills remain a threat.

Global Short Term Trend: Decline of 10-30%

Comments: Has declined significantly in the past--some colonies have been eliminated by introduced mammalian predators. In Alaska, "vast numbers" were extirpated when foxes were introduced to islands (Manuwal and Thoresen 1993; Springer ET AL. 1993). Manuwal and Thoresen (1993) state that Alaska formerly had more breeding birds than British Columbia (2.7 million), but fewer than 600,000 remain today. Evidence for recent trends is conflicting. On the Farallon Islands, California, populations declined 65% from 1972-1997 (Nur et al. 1998). At Triangle Island, British Columbia, the world's largest breeding colony, the estimated survival rate from 1994-1997 "appears lower than that required for the maintenance of a stable population" (Bertram et al. 2000). In northern British Columbia, however, survival rates are higher and there is no evidence of population change (Bertram et al. 2000). Some colonies continue to decline in British Columbia because of rat and raccoon predation (B.C. Conservation Data Centre). Colonies are sometimes "temporarily vacated, during periods of warm oceanographic conditions" (Manuwal and Thoresen 1993).

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Introduced arctic foxes caused declines on some Alaska islands, but may be recovering with foxes now gone from many islands (see Johnsgard 1987, Lensink 1984). Raccoon predation a threat to 80% of British Columbia occurrences, representing 20% of the population (B.C. Conservation Data Centre). Long-term oceanographic changes and consequent declines in the California Current zooplankton populations are thought to be the cause of the decline on the Farallon Islands, California, and a probable decline at Triangle Island, British Columbia, the world's largest Cassin's Auklet colony (Bertram et al. 2000). Oil spills are a significant threat (Burger 1992). In Mexico, livestock grazing causes burrow destruction and erosion in colonies. Walking in colonies causes burrows to collapse and may crush birds; disturbance at burrow may cause abandonment of the egg (Manuwal and Thoresen 1993).

Biological Research Needs: Research is needed on characteristics of reproduction for colonies outside British Columbia and California. More research needed into mortality from drowning in gill nets.

Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Comments: Several large colonies in British Columbia not protected.

Needs: Major unprotected colonies (e.g., Frederick and Lihou islands in British Columbia) should be protected.