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The Common Murre, a remarkable seabird of the North Atlantic and North Pacific, is a species that has captivated ornithologists and bird enthusiasts alike. With its striking black and white plumage and distinct breeding and nonbreeding adult characteristics, the Common Murre presents a fascinating subject for study.

These birds exhibit remarkable physical adaptations for their oceanic lifestyle, including their exceptional diving abilities and their unique nesting behaviors on sheer cliffs.

Moreover, their vocalizations during courtship and their seasonal movements provide further insight into the complex and intriguing world of the Common Murre.

This species offers a window into the wonders of avian biology and behavior, making it a compelling subject for further exploration.

Key Takeaways

  • Common Murres are large black-and-white seabirds with a distinctive appearance and nesting habits.
  • They have a unique black head and long, thin bill during the breeding season, but their throat, chin, and cheeks turn white in the nonbreeding season.
  • Common Murres have an upright stance similar to a penguin and nest in colonies on steep cliffs, slopes, and rocky outcrops.
  • They have specialized adaptations, such as a sleek body, long bill, and narrow wings, for underwater agility, prey capture, and deep diving.

Murre Identification and Overview

understanding murre characteristics and behavior

The Common Murre is a large black-and-white seabird with a unique look and nesting habits. This bird is recognized by its completely black head and long, thin bill during breeding season, whereas its throat, chin, and cheeks turn white, extending to the area behind its eyes in nonbreeding season.

The Common Murre, often seen in an upright stance similar to a penguin, nests in colonies on steep cliffs, slopes, and rocky outcrops and generates a constant flow of guttural calls. In the Atlantic region, this bird can be identified by a white eyering across its face, known as the bridled form.

The species is primarily seen in Pacific nesting subspecies such as californica and inornata, along with the smaller aalge subspecies in the Atlantic. The bird spends most of its life in the open ocean, often far from land, and breeds on cliffs and islands by the sea.

Distinctive Physical Characteristics of Murres

Murres, known for their unique physical characteristics, are easily identifiable. They exhibit a striking black-and-white appearance, and the breeding adults have a long, thin bill with a penguin-like upright stance.

The nonbreeding adults and immature birds, on the other hand, resemble ducks with a slender body and bill, and distinct facial markings. A white eyering that extends across the face, known as the bridled form, is a trait of breeding adults in the Atlantic region. Their nesting practices involve forming colonies on steep cliff ledges, slopes, and rocky outcrops, and they frequently make guttural calls at the colony.

The nonbreeding adults and immature birds portray a pale throat and face with a dark line behind the eye, and some Atlantic adults exhibit a bridle: a white eyering with a white line extending behind it. These distinctive physical traits facilitate the identification and understanding of the Common Murre in its natural habitat.

Anatomy and physiology

study of body structure

The Common Murre, also referred to as the thick-billed murre, exhibits a unique anatomy and physiology that allows it to thrive in the marine environment. This bird displays a multitude of specialized characteristics that facilitate efficient diving, swimming, and capture of prey.

The body of the Common Murre is sleek and torpedo-shaped, a design that enhances its underwater agility. The bird possesses a long, slender bill, a feature specifically evolved for seizing and retaining slippery prey. Coupled with its narrow, pointed wings, the Common Murre can descend to depths exceeding 600 feet.

Physiological adaptations, including effective oxygen utilization and buoyancy control mechanisms, enable the bird to endure the pressures of deep-sea diving. The digestive system of the Common Murre is internally optimized to process its primary diet of fish. This system contains specialized anatomical features that ensure effective digestion and nutrient absorption.

These combined adaptations equip the Common Murre to skillfully traverse the marine environment, while also possessing the ability to fly and return to its nesting sites on sea cliffs or flat bare.

Black and White Plumage Patterns

distinctive bird coloration patterns

Common Murre breeding adults display black and white plumage patterns. They have large black-and-white bodies and entirely black heads. Nonbreeding adults and immature birds have a different pattern. They show a white throat, chin, and cheek that extends up behind the eye.

The breeding birds have a blackish head, face, and upper parts. The lower parts remain pure white. Some populations of Common Murres in the Atlantic, when in their breeding plumage, display all-brown faces. However, exceptions exist with bridled individuals that have a white eyering and a white line extending backward from the eyes.

These plumage patterns play a vital role in their survival. They provide camouflage against predators both from above and below in the sea. The Common Murre, a bird species common along the Pacific coast, relies heavily on these patterns.

However, climate change threatens these distinctive plumage patterns. Changes in oceanic conditions might affect their foraging and breeding areas. This impact could affect their ability to retain these sharp black-and-white markings.

Breeding and Nesting Habits

avian reproduction behaviors

Common Murres, during their breeding period, establish populous colonies on high cliff edges, inclines, and stony protrusions. They exhibit their adaptability and inventiveness by laying eggs directly on the bare rock, without the need for a conventional nest. This social and communicative species frequently emits throaty calls at these colonies.

The bridled form of Common Murres, distinct with a white eyering extending across the side of their face, is predominantly observed in the Atlantic region. This provides an interesting aspect to their breeding behavior.

Parental instincts and adaptations of Murres are evident in the unique colors and patterns of their eggs. These help them identify their own amidst the crowded cliff ledges.

Seasonal Movement Patterns

migratory patterns of animals

The seasonal movement patterns of the Common Murres are rooted in their breeding habits.

In the winter, these seabirds migrate southwards from their northern colonies in western Alaska, reaching areas like New England waters and southern California, following the Pacific and Atlantic coasts.

Despite this seasonal migration, many Common Murres remain in certain areas throughout the year, especially along the West Coast in cool ocean waters.

The subspecies of the Pacific-nesting Common Murres, such as californica and inornata, display regional seasonal movements. While californica breeds from California to southern British Columbia, inornata breeds from northern British Columbia to Alaska and eastern Asia.

The seasonal movement patterns of these two subspecies is believed to be a result of the separation of the Atlantic and Pacific groups since the Pleistocene period.

Murre Vocalization During Courtship

Common Murres, during courtship, vocalize guttural calls. These low, grunting sounds contribute to pair bonding and territorial communication. These sounds frequently accompany displays such as bowing, billing, and preening between partners.

These courtship vocalizations and displays help in the creation and sustainment of pair bonds. They also function as a territorial defense method and a means for communication in the densely populated colonies where these birds nest.

The Common Murre, recognized for its diligent parenting and breeding behavior, possesses a white-lined, egg-shaped form.

Cornell Lab provides updates about birds and ways to assist bird conservation efforts, offering valuable data about the Common Murre and other bird species.

Frequently Asked Questions

Are Common Murres Related to Penguins?

In response to the question of whether Common Murres are related to penguins, genetic studies demonstrate they are not closely related. Despite physical similarities, the relation between Common Murres, predominantly found in the Northern Hemisphere, and penguins, primarily located in the Southern Hemisphere, is not close.

How Do You Identify a Common Murre?

Identifying a Common Murre involves looking for a large bird that is black and white in color. This bird will have a long, thin bill and will stand upright in a manner similar to a penguin. For those in their breeding phase, a black head is a distinguishing feature. Conversely, those not breeding will show a white throat, chin, and cheek.

Where Do Common Murre Live?

Common Murres inhabit the steep, cliff ledges, slopes, and rocky outcrops along the Pacific and Atlantic coasts. These seabirds are known for spending the majority of their lives on the open ocean, often venturing far offshore. Their colonies are typically located in areas that facilitate breeding.

Are Common Murres Endangered?

Common Murres are not endangered. The threat they face includes oil spills, pollution, overfishing, and climate change. However, the IUCN classifies them as least concern due to their large and abundant populations in North America and Europe.

What is the difference between a Common Murre and a Common Loon?

The key difference between a Common Murre and a Common Loon lies in their bird behavior and habitat. Common Murres are seabirds that nest on cliffs and feed in the ocean, while Common Loons are freshwater birds that inhabit lakes and ponds. Their behaviors and habitats are distinct due to these differences.

Conclusion

In conclusion, the Common Murre is a large seabird with distinctive black and white plumage, known for its guttural calls and nesting habits on steep cliffs and rocky outcrops.

These expert swimmers and divers feed on fish and can be found in the open ocean and along coastlines.

However, the species is vulnerable to pollution and the effects of climate change, leading to declines in some areas.