Bird

Aleutian Tern

Onychoprion aleuticus

Aleutian terns nest colonially along coastal marshes, gravel spits, and islands of the northern Pacific, often mingling within larger colonies of Arctic terns. Unlike their bolder relatives, they exhibit a wary demeanor and produce soft, whistling, cricket-like calls rather than harsh shrieks. Long-distance migrants, they undertake extensive trans-equatorial journeys each autumn to spend the non-breeding season across the tropical waters of Southeast Asia.

MigratorySeabirdColonial

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VulnerableConservation status

Key facts

Diet & preyPacific Sand Lance, Capelin, Euphausiids

Predators

Glaucous-winged Gull
Common Raven
Red Fox

ThreatsNesting colony disturbance, coastal development, predation by introduced mammals, and marine prey shifts

HabitatsCoastal tundra, gravel beaches, barrier islands, and pelagic waters

Life span15–20 years

Classification

FamilyLaridae
SpeciesOnychoprion aleuticus

Range & activity

Range data is not available yet.

Safe observation

Interaction riskLow

Low
Moderate
High
Very high

Why interaction risk is low: Safe to observe at a normal distance.
What to notice: Recognizable among terns by a dark gray back, a crisp white forehead patch contrasting with a black cap, and entirely black bill and legs.
Support conservation: Keep at least 100 meters away from potential nesting spits and immediately retreat if birds take flight in distress.

Responsible observation

Maintain Shoreline Distance: Stay well back from coastal nesting grounds between May and August to avoid causing egg abandonment.
Listen for Quiet Calls: Distinguish them from noisy Arctic terns by listening for their distinctively mellow, chirping vocalizations.
Scan for Black Legs: Look for black bills and legs to tell them apart from bright-red Arctic tern adults.

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