Marine Bird Guide: The Auks
Tufted Puffins, Photo by Captain Yves, image taken with zoom lens and heavily cropped.
  • June 11, 2019

Today’s post is all about Auks!

Auks are a group of marine birds, also known as alcids. They include murres, guillemots, auklets, puffins, and murrelets. These birds are all wing-propelled diving birds, meaning that they dive underwater to feed using their wings to swim.

Scroll down to learn about:

  • Common Murres
  • Rhinoceros Auklets
  • Cassin’s Auklets
  • Tufted Puffins
  • Marbled Murrelets

Check out our post on Common Marine Birds to learn about the Pigeon Guillemot, another auk species you may see on our tours.

Common Murre

Latin name: Uria aalge

"Common Murre (Uria aalge)" by sussexbirder is licensed under CC BY 2.0
“Common Murre (Uria aalge)” by sussexbirder is licensed under CC BY 2.0

Distinguishing Features:

A crow-sized bird with black plumage and white underside. It vaguely looks like a penguin, with a long thin bill. During the non-breeding months (winter) these birds will have more white on their face and body whereas they will be mostly black in the summer.

Maximum Size and Age:

Length: 15.0-16.9 in (38-43 cm), Wingspan: 25.2-27.9 in (64-71 cm).

The oldest on record was 27 years and 1 month, banded and recaptured in California.

Fun Facts:

  • The Atlantic variety will sometimes have a white ring and line extending back from the eye; this is called bridled plumage.
  • There is so much variety in eggs colour and spotting that mothers may be able to recognize their eggs when returning from sea.
  • The eggs are very pointed at one end. When flat on the ground they will only roll in a circle. The eggs are shaped this way as it prevents them from rolling off of the cliffs where Common Murres nest.

Common Behaviour:

Common Murres nest on rocky cliffs and spend their winters at sea. You may see them gathering at sea over schools of fish or near their breeding grounds in the summer.

Conservation Status:

Common Murres are abundant yet they are vulnerable to oil spills and gill-netting. The North American population is estimated at over 4.25 million individuals. While populations have declined in the past they are currently increasing in the Atlantic and partially recovered in the Pacific.

Rhinoceros Auklet

Latin name: Cerorhinca monocerata

"Rhinoceros Auklet" by GregTheBusker is licensed under CC BY 2.0
“Rhinoceros Auklet” by GregTheBusker is licensed under CC BY 2.0

Distinguishing Features:

A close relative of puffins, Rhinoceros Auklets have a distinct bump on their bill, resembling a Rhinoceros’ horn.

Maximum Size and Age:

Length: 11.0-11.4 in (28-29 cm), Wingspan: 23.2-24.4 in (59-62 cm). The oldest Rhinoceros Auklet was 28 years old. It was originally banded in British Columbia and later found in Oregon.

Fun Facts:

Rhinoceros Auklets bring food back to their nests at night, in an effort to avoid scavengers like gulls from stealing their food.

Common Behaviour:

A pelagic open ocean species, Rhinoceros Auklets spend the majority of their live on the ocean. They will return to land to nest in burrows on islands.

Conservation Status:

Oils spills and mammals, like racoons, have eliminated entire colonies in some cases. However, Rhinoceros Auklets are listed as a low concern for conservation relative to other species of marine birds.

Cassin’s Auklet

Latin name: Ptychoramphus aleuticus

"Cassin's Auklet" by bgwashburn is licensed under CC BY 2.0
“Cassin’s Auklet” by bgwashburn is licensed under CC BY 2.0

Distinguishing Features:

Cassin’s Auklet feathers are dark on their back and light on their underside. Cassin’s Auklets have no distinct markings other than the small white mark above their eye.

Maximum Size and Age:

The oldest on record was 16 years old when it was found in California.

Fun Facts:

Cassin’s Auklets nest on offshore islands, the most significant colony being off the northern tip of Vancouver Island on Triangle Island. This is a sociable bird species, usually found in flocks and colonies.

Common Behaviour:

In the southern end of their range along the Pacific Coast of North America Cassin’s Auklets will spend time at their nesting colonies every month. It is unusual for marine birds to spend so much time at the breeding colony year round, though this means pairs can produce two broods per breeding season.

Conservation Status:

Threats include introduced predators, like foxes, cats, and rats, as well as changing ocean temperatures. Cassin’s Auklets are listed as near-threatened on the IUCN red list. Overall their conservation status suffers from a lack of information but appears to be declining.

Tufted Puffin

Latin name: Fratercula cirrhata

Tufted Puffins
Tufted Puffins, Photo by Captain Yves, image taken with zoom lens and heavily cropped.

Distinguishing Features:

Tufted Puffin’s have a white face mask and large orange bill. Their namesake feature is the pair of long golden feathers that extend over their eyes and off the back of the head. These tufts are only present during the breeding season.

Maximum Size and Age:

The oldest on record was 6 years old and found in Alaska. Length: 14.2-15.8 in (36-40 cm).

Fun Facts:

  • Tufted Puffins dig deep burrows into cliffs and slopes for nesting. The burrows can be more than 1.5 m long.
  • Adults will eat their food underwater as soon as it is captured. When bringing food back to their young they will hold several fish cross-wise in their bill.

Common Behaviour:

An open water bird, they will dive for food. Tufted Puffins eat small fish as well as invertebrates. Nestlings (young puffins) prefer fish and adults will eat more invertebrates like squid and krill.

Conservation Status:

There is limited information about population trends, they are abundant and is low concern in the continental concern score. Tufted Puffins are vulnerable as bycatch, also may be taken out by predators like foxes, River Otters, Brown Bears and other mammals. Tufted Puffins survive best on islands where the predators have not been introduced.

Marbled Murrelet

Latin name: Brachyramphus marmoratus

"Marbled Murrelet" by USFWS Headquarters is licensed under CC BY 2.0
“Marbled Murrelet” by USFWS Headquarters is licensed under CC BY 2.0

Distinguishing Features:

A small and plump seabird, with a short pointed bill. They have mottled black, brown and light plumage. Marbled Murrelets will turn darker during breeding season.

Maximum Size and Age:

A medium to small bird, Length: 9.4-9.8 in (24-25 cm).

The oldest on record was 10 years old. It was banded and recaptured in British Columbia.

Fun Facts:

Marbled Murrelets were suspected to nest in old growth trees but this was not confirmed until a tree climber found a chick in 1974. They prefer to nest in trees that are at least 200 years old or more.

Common Behaviour:

Commonly seen near forested coastlines during the breeding season. They prefer old-growth coniferous forests as nesting habitat. Marbled Murrelets will winter at sea like most marine birds.

Conservation Status:

Limited information is available on the status of this species. However, they appear to be in decline and are listed as endangered on the IUCN red list. Logging and development in forest habitat are the biggest threats to the species. Oil spills and entanglement in fishing gear, like gill-nets, are also threats as they are for many marine birds species.


Check out our other blog post about Marine Birds here.

Facts courtesy of The Cornell lab of Ornithology “All about Birds”.

Written by Stefania, Marine Biologist

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