Ptychoramphus aleuticus
Silhouette: Sheatherius · PhyloPic
In 3 days ~10% in a week ~20%
Cassin's auklet (Ptychoramphus aleuticus) is a small, chunky seabird that ranges widely in the North Pacific. It is the only species placed in the genus Ptychoramphus. It nests in small burrows and because of its presence on well studied islands in British Columbia and off California it is one of the better known auks. It is named for the American ornithologist John Cassin.
Cassin's auklet is a small (25 cm, 200 g) nondescript auk. Its plumage is generally dark above and pale below, with a small white mark above the eye. Its bill is overall dark with a pale spot, and its feet are blue. Unlike many other auks, Cassin's auklet lacks dramatic breeding plumage, remaining the same over most of the year. At sea it is usually identified by its flight, which is described as looking like a flying tennis ball.
Cassin's auklet ranges from midway up the Baja California peninsula to Alaska's Aleutian Islands, off North America. It nests on offshore islands, with the main population stronghold being Triangle Island off Vancouver Island's Cape Scott, where the population is estimated to be around 55,0000 pairs. It is not known to be migratory. However, northern birds may move farther south during the winter.
Two subspecies are recognised: An extinct relative or predecessor species, Ptychoramphus tenuis L. H. Miller et Bowman, 1958, is known from the Late Pliocene of the San Diego Formation in California. Wikipedia →
Song0:41
United States · 2023
© Matthew L. Brady · XC842473 · CC BY-NC-SA 4.0
Recording0:32
Mexico · 2022
© Álvaro San José Elizundia · iNaturalist · CC BY-NC 4.0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Bear Rainforest | 🇨🇦 Canada | |
| 2 | Channel Islands National Park | 🇺🇸 United States | |
| 3 | Olympic National Park | 🇺🇸 United States | |
| 4 | Pacific Rim National Park Reserve | 🇨🇦 Canada |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Diego | 🇺🇸 United States | |
| 2 | Seattle | 🇺🇸 United States | |
| 3 | Los Angeles | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Cassin's Auklet sighting in Channel Islands National Park on a given day, based on 144 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 151st most-seen of the 276 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
May and October–November
In those months about 10% of wildlife watchers report a Cassin's Auklet in Channel Islands National Park on a given day, against under 5% in June–September and December–April, the lowest months. Those are among Channel Islands National Park's driest months, with about 10 mm of rain a month against 60 mm in January.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Cassin's Auklet sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 4 parks where we can rate Cassin's Auklet sightings, Channel Islands National Park ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Great Bear Rainforest (Canada, under 5%).
GBIF citizen-science records
It is estimated from how often the Cassin's Auklet is recorded against all the birds logged in Channel Islands National Park (144 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
