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Thick-billed Murre: Identification and Overview

July 17, 2023

Title: The Marvel of the Arctic Skies: An In-Depth Look at the Thick-Billed Murre

Size and Shape:Belonging to the auk family, the Thick-billed Murre shares a similar body structure to penguins, although they are not closely related. These birds exhibit a streamlined body that is conducive to a life spent predominantly in marine environments. They boast a sizeable body that can reach lengths of 40 to 48 cm (15.7 to 18.9 in), exhibiting an impressive balance between size and agility. With wingspans that stretch up to 61-73 cm (24-28.7 in), these birds are designed for both flying and swimming, striking a balance that is truly extraordinary.

The Thick-billed Murre possesses a strong, pointed beak, a feature that distinguishes it from its closest cousin, the Common Murre. This thick, heavy bill has bestowed the bird with its name, serving as an essential tool for hunting and feeding. Alongside this, the bird’s overall shape demonstrates a fascinating evolution for a life at sea. Their short legs are situated far back on their body, optimized for paddling in water, rather than walking on land.

In contrast to their graceful flight and adept swimming, on land, Thick-billed Murres can appear somewhat awkward. They exhibit an upright stance similar to penguins, further adding to their initial comparison. Yet, despite their clumsiness on land, they demonstrate remarkable agility when navigating cliff faces, their primary nesting sites. There, they balance on narrow ledges with a surprising sure-footedness, truly indicating their adaptability to diverse environmental conditions.

Their overall body shape, complete with a robust torso and strong wings, is an evolutionary design aimed at survival in the harsh Arctic conditions. It represents a successful adaptation to a lifestyle that demands both aerial and aquatic proficiency.

Color Pattern:An immediate striking characteristic of the Thick-billed Murre is its unique color pattern. Like a well-tailored suit, the bird showcases a sharp contrast of colors, presenting a sleek black upper body and a white underbody. This form of coloration, known as countershading, provides effective camouflage while they're in the water, protecting them from predators above and below.

The thick bill, for which this species is named, is dark and accented by a thin, white line during the breeding season, a detail that separates it from other members of the auk family. The rest of the year, the white line disappears, and the bill becomes uniformly dark. Thick-billed Murres possess dark brown eyes that give them a focused and determined look, mirroring their resilient character.

During the breeding season, their black plumage adopts a slight greenish sheen, further enhancing their distinctive look. Their feet, though mostly hidden when in flight, are a dark shade of grey, matching the color of their upper body. Immature birds differ slightly in color, exhibiting a dark grey back and a white belly.

These color patterns are not just aesthetically pleasing; they serve a purpose for the birds. Their contrasting shades offer them effective camouflage in the water, allowing them to avoid detection by predators and prey alike.

Behavior:Thick-billed Murres are intriguing not just in their physical attributes but also in their behavioral traits. These birds are known for their sociability, often seen in large colonies during the breeding season. Their communal living extends to their nesting habits, where they gather in thousands on steep cliff faces, taking advantage of the security from ground predators that these locations provide.

One of the most compelling aspects of their behavior is their deep diving ability. Thick-billed Murres are among the world's deepest diving birds, capable of reaching depths over 200 meters to catch their prey. They primarily feed on fish and invertebrates, using their wings to 'fly' underwater in pursuit of their quarry.

The Thick-billed Murre's parenting behavior is another fascinating aspect. Unlike many bird species, both parents participate in incubating the single egg and feeding the chick once it hatches. Remarkably, the male murre takes over the primary care of the chick once it leaves the nest, accompanying it to the wintering grounds and supervising its feeding.

Their migratory behavior is also noteworthy. Outside the breeding season, Thick-billed Murres disperse across Arctic and subarctic waters, often traveling several thousand kilometers. Yet, despite this broad distribution during non-breeding times, they typically return to the same breeding sites year after year, exhibiting a strong site fidelity.

Habitat:When it comes to their habitat, Thick-billed Murres are true Arctic dwellers. Their breeding colonies are located in the High Arctic across the Northern Hemisphere, from the coasts of Alaska and Canada, across Greenland, and over to the northern parts of Eurasia. These colonies are often situated on steep, rocky cliffs overlooking the ocean, providing the birds with immediate access to hunting grounds and a degree of protection from predators.

While they may seem to prefer the solid ground for nesting, the Thick-billed Murre is fundamentally a marine bird, spending the majority of its life at sea. The open ocean is their playground and pantry, offering them a rich diversity of food sources such as fish and marine invertebrates. The frigid Arctic waters do not deter these hardy birds; rather, they are remarkably adapted to this icy environment.

In winter, they tend to venture to the edge of the sea ice, where they can find open water for foraging. They're also known to frequent polynyas, areas of open water surrounded by ice, which serve as rich feeding grounds. Although they can travel far during non-breeding periods, they are always bound to the sea, highlighting their inherent connection to marine environments.


  1. The Thick-billed Murre, while resembling a penguin in appearance and behavior, is not a penguin at all. Penguins are found exclusively in the Southern Hemisphere, while Thick-billed Murres inhabit the Northern Hemisphere.
  2. They are incredible divers. In fact, one Thick-billed Murre holds the record for the deepest known dive of any bird, plunging to an astounding 210 meters (nearly 700 feet) below the surface of the sea.
  3. Despite their somewhat clumsy appearance on land, Thick-billed Murres are quite agile flyers. They can reach flight speeds of up to 75 km/h (46.6 mph), displaying remarkable prowess in the air.
  4. In a unique twist to their parenting behavior, once the chick is old enough to leave the nest but not yet capable of sustained flight, it will leap off the cliff edge and glide down to the sea with the male parent. This dramatic plunge often happens from heights of several hundred meters.
  5. These birds exhibit strong site fidelity. Studies have found that they usually return to the same exact nesting spot year after year. Remarkably, some birds have been found returning to the exact same nesting site for over 20 years.

Ecosystem Services:Thick-billed Murres play crucial roles in the ecosystems they inhabit. As predators, they help control populations of fish and marine invertebrates, contributing to the overall balance of the marine food web. Their excrement, or guano, enriches the soil in and around their colonies, providing vital nutrients for terrestrial plant life.

Moreover, they serve as a vital food source for various Arctic predators, including foxes, polar bears, and large birds of prey. Even their eggs are not spared, often collected by gulls and humans alike. Thus, they contribute to the energy flow within their ecosystem, underpinning the survival of various other species.

Their nesting colonies also influence the physical environment. The sheer number of birds that congregate on cliff faces during the breeding season can lead to significant erosion, altering the landscape over time. In addition, their presence on these cliffs discourages some potential predators, providing a safer environment for other cliff-nesting birds.

Conclusion:The Thick-billed Murre, a true marvel of the Arctic skies, exhibits an array of fascinating characteristics. From its distinctive shape and color pattern to its unique behavioral traits and crucial ecological roles, this bird truly captivates those who take the time to study it. Though it may face challenges due to climate change and human activities, it continues to demonstrate remarkable resilience, truly embodying the spirit of the Arctic. As we continue to explore and appreciate the natural world, species like the Thick-billed Murre serve as a constant reminder of the planet's astounding biodiversity and the importance of conservation efforts.