Rea's Auklet

Cerorhinca reai

Order: Charadriiformes / Family: Alcidae

Wikimedia Commons

gray black white medium seabird coastal colonial migratory nocturnal rare endangered widespread

About the Rea's Auklet

Rea's Auklet, scientifically known as Cerorhinca reai, is a fascinating member of the Alcidae family. This seabird is primarily found in the northern Pacific, where it inhabits coastlines and islands. The species is notable for its exceptional diving ability, which it uses to forage for food underwater. Rea's Auklet displays a strong ecological role in its environment, serving as both a predator and prey. As a predator, it controls fish and invertebrate populations, while as prey, it supports various marine predators, including larger birds and marine mammals.

The significance of Rea's Auklet extends beyond its ecological contributions. It is an indicator species for marine ecosystem health. Changes in its population can signal shifts in oceanic conditions, including prey availability and water quality. This auklet is primarily found in regions such as the Aleutian Islands and coastal Alaska. During the breeding season, it forms large colonies on remote islands, nesting in crevices and burrows.

Rea's Auklet exhibits seasonal behaviors, with large-scale movements occurring outside the breeding season. In winter, it often disperses to offshore waters, sometimes moving southward depending on sea conditions. The auklet's adaptability to different marine environments highlights its resilience, yet it remains vulnerable to threats such as oil spills and climate change, which may alter its habitat and food supply.

The Rea's Auklet belongs to the family Alcidae, within the order Charadriiformes. These birds typically live average 8 years, with a maximum recorded of 12 years..

How to Identify a Rea's Auklet

Adult Rea's Auklet features a distinctive black and gray plumage with a slightly tufted crest on its head. Its bill is short and robust, ideal for its piscivorous diet. The eyes of Rea's Auklet are surrounded by a thin white ring, adding to its striking appearance. The difference between males and females is subtle, with males generally displaying slightly brighter plumage during the breeding season.

Juveniles lack the prominent crest found in adults and exhibit duller plumage overall. They can be confused with other auklets, such as the Whiskered Auklet, but Rea's Auklet's bill structure and size are distinguishing features. In flight, Rea's Auklet presents a compact silhouette with rapid wingbeats, a characteristic shared by many alcids. When perching, its posture is upright, often on rocky ledges or low branches near water.

The auklet's size, typically around 25 cm in length, places it in the medium-sized category among seabirds. Its wingspan, roughly 45 cm, contributes to its efficient diving and strong flight capabilities, aiding its survival in the demanding marine environment.

Having trouble telling birds apart? Upload a photo to our bird identification tool for an instant species match.

Rea's Auklet Habitat and Range

Preferred Habitat

Rea's Auklet thrives in coastal and offshore environments of the North Pacific. Its preferred habitats include rocky islands and cliff faces, where it can nest in crevices and burrows. These areas provide both protection from predators and access to abundant marine prey.

The auklet is primarily found at sea levels up to 300 meters, rarely venturing inland. During the breeding season, it congregates on isolated islands, avoiding human disturbances. In winter, Rea's Auklet shifts towards open waters, often traveling considerable distances in search of food-rich areas.

Unlike urban-dwelling birds, Rea's Auklet is strictly marine and does not adapt to urban environments. Its presence in rural coastal areas underscores its dependence on natural, undisturbed habitats for survival. Seasonal habitat shifts are dictated by food availability and environmental conditions, requiring adaptability to varying marine ecosystems.

Geographic Range

Rea's Auklet breeds primarily in the northern Pacific, with a distribution that includes the Aleutian Islands, the Bering Sea, and coastal regions of Alaska. During the breeding season, large colonies form on remote islands, where the auklets nest in burrows and crevices.

In the non-breeding season, Rea's Auklet disperses into offshore waters, ranging southward to areas such as the northern coast of British Columbia. Its wintering range is less defined but includes regions with abundant marine life, as it follows food sources.

Migration corridors are primarily marine, with auklets traveling along the continental shelf to reach wintering grounds. Population density is highest in breeding colonies, which can support thousands of individuals. These hotspots are crucial for maintaining the species' population, as they provide safe nesting sites and access to rich feeding grounds.

Want to know which birds visit your area? Browse our backyard birds by location guides for region-specific species lists.

What Does the Rea's Auklet Eat?

Rea's Auklet primarily consumes small fish and marine invertebrates. Its diet includes species such as sand lance and krill, which are abundant in its marine habitat. During the breeding season, the auklet's diet consists mostly of fish, providing the necessary nutrients for chick development.

In winter, Rea's Auklet may shift to a diet more heavily reliant on invertebrates, as fish populations fluctuate seasonally. The auklet employs a diving technique to forage, using its strong wings to propel itself underwater in pursuit of prey. Typically, it forages at depths of up to 30 meters, although it can dive deeper if necessary.

The auklet's feeding schedule is influenced by tidal cycles, with increased activity during low tides when prey is more accessible. Its foraging efficiency and adaptability to different prey types are vital for its survival in the variable marine environment.

Rea's Auklet Behavior and Social Structure

Rea's Auklet is highly social, often found in large flocks during the breeding season. Its social structure revolves around nesting colonies, where individuals engage in cooperative behaviors like group foraging and predator defense. The auklet exhibits territorial behavior around nesting sites, with pairs defending their burrows from intruders.

Courtship displays involve vocalizations and physical posturing, with males often presenting food to females as part of the bonding process. Flocking patterns are evident during migration, as groups move together through offshore waters, reducing predation risk.

The auklet responds to predators with alarm calls and evasive maneuvers. Its daily activity pattern involves alternating periods of feeding and resting, with peak activity occurring during dawn and dusk. Rea's Auklet's social and territorial behaviors are crucial for its breeding success and survival in the wild.

Rea's Auklet Nesting and Reproduction

Rea's Auklet nests in crevices and burrows on rocky islands, often in large colonies. These nests are constructed using natural materials like rocks and vegetation, providing insulation and protection. The auklet prefers locations that offer security from predators and proximity to food sources.

Clutch size for Rea's Auklet typically consists of one to two eggs, with incubation lasting around 35 days. Both parents share incubation duties, taking turns to forage and protect the nest. Once hatched, chicks remain in the nest for approximately 30 to 40 days before fledging.

Parental roles are shared, with both adults feeding and protecting the chicks. Rea's Auklet generally produces one brood per year, although favorable conditions can lead to occasional second broods. Successful nesting requires cohesive parental cooperation and suitable environmental conditions.

Rea's Auklet Sounds and Vocalizations

Rea's Auklet produces a variety of vocalizations, with its primary song characterized by a series of rhythmic, low-pitched calls. These sounds serve both social and territorial functions, often heard during courtship and nesting.

Call notes are sharp and distinct, used as communication within flocks and during foraging. Alarm calls are louder and more urgent, triggered by the presence of predators. During the dawn chorus, Rea's Auklet's calls blend with those of other seabirds, creating a dynamic soundscape.

The auklet's vocalizations can be compared to the soft cooing of doves, but with a more resonant quality. Understanding these sounds provides insights into the auklet's social interactions and environmental awareness.

Interesting Facts About the Rea's Auklet

1Rea's Auklet can dive to depths of up to 30 meters and remain underwater for over a minute in pursuit of prey.
2During the breeding season, Rea's Auklet forms colonies that can number several thousand individuals, creating bustling nesting grounds.
3Unlike many seabirds, Rea's Auklet's courtship involves mutual displays and vocal exchanges, strengthening pair bonds.
4Rea's Auklet spends most of its life at sea, only coming ashore to breed, making it a true pelagic species.
5The auklet's feet are positioned far back on its body, aiding in powerful swimming but making land movement awkward.
6Rea's Auklet's distinctive plumage helps it blend into rocky coastal environments, providing camouflage from predators.
7The auklet's diet includes both fish and invertebrates, allowing it flexibility in varying marine conditions.

Rea's Auklet Conservation Status

Rea's Auklet currently holds a status of least concern on the IUCN Red List, with a stable population trend. However, it faces threats from oil spills, fishing net entanglements, and habitat degradation. Conservation efforts focus on protecting breeding sites and reducing pollution in marine environments. Historical population changes reflect the species' resilience, with numbers rebounding following past declines due to hunting and habitat disturbance. Ongoing monitoring and research are crucial for maintaining population stability, particularly as climate change poses new challenges to its habitat and food sources.