Swallow-tailed Gull: where and when to see them

The swallow-tailed gull is a distinctive seabird centered on the Galápagos, with a smaller breeding presence on Colombia's Malpelo Island. Its deeply forked tail, large eyes and striking breeding plumage set it apart from most gulls. Unusually, it feeds mainly at night, exploiting prey near the ocean surface. Birds resting on rocky shores during daylight are therefore often between nocturnal feeding trips rather than preparing to forage along the beach.

Size

51–58 cm long

Weight

610–780 g

Lifespan

Not reliably established

Status

Least Concern

Pairs nest on rocky ledges, slopes and cliff margins, often among loosely grouped neighbors. Courtship includes calling, head movements and food presentation, and both parents share incubation and chick care. Breeding is not tightly synchronized across the archipelago, so colonies can contain birds at different stages. At sea, feeding largely takes place after dark. During daylight, adults may sleep, preen or attend their single chick close to the nest site. Chicks are semi-precocial, meaning they are relatively helpless at hatching and rely heavily on parental care. Adults exhibit a unique 'wing-spread' display to defend their nests from perceived threats. They are highly vocal, especially near the colony, using a variety of calls for communication and alarm.

• It is the only species in the genus Creagrus.
• Its unusually large eyes support feeding in low light.
• A normal clutch contains just one egg.
• Breeding adults lose the dark hood when out of breeding plumage.

Galápagos observation is possible throughout the year because breeding schedules differ among colonies and pairs. Local nest attendance is more informative than a single archipelago-wide season. Weather, sea conditions and authorized visitor itineraries determine which colonies can be viewed on any particular trip. While specific colony activity varies, sightings from cruise ships are consistent year-round across the Galápagos archipelago. Observing different breeding stages within a single colony is common due to asynchronous nesting patterns. Ship-based viewing offers opportunities for close encounters as they often follow vessels at sea.

Breeding habitat consists of rocky oceanic islands with open ledges, cliffs and sparsely vegetated slopes. Outside nesting areas, the gull uses offshore tropical Pacific waters. Sheltered colony edges can be visible from authorized paths, but many cliff nests remain inaccessible. This pelagic species spends most of its non-breeding life at sea, foraging over deep oceanic waters. Its range extends across the tropical eastern Pacific, from Colombia to Peru and oceanic islands. Preferred nesting sites offer protection from predators and human disturbance, often on cliffs or steep slopes.

Small fishes and squid form the main diet, captured at or near the sea surface. Nocturnal feeding takes advantage of prey that move upward after dark. Unlike many familiar gulls, this species is not primarily a beach scavenger or refuse feeder. Their large eyes are adapted for excellent nocturnal vision, aiding in the capture of bioluminescent squid and fish. These gulls are unique among gulls for their predominantly nocturnal foraging strategy. Prey items are typically small enough to be swallowed whole, minimizing handling time at sea.

Common name

Swallow-tailed Gull

Scientific name

Creagrus furcatus

Animal group

Birds

Size

51–58 cm long

Weight

610–780 g

Lifespan

Not reliably established

Status

Least Concern

Identification

The deeply forked tail, red eye-ring and dark breeding hood distinguish it from the smaller, square-tailed lava gull. Juveniles are distinguished by their black head, duller eye ring, and mottled brownish plumage, gradually developing adult features over several years. The long, slender wings and buoyant flight are also characteristic, making them appear graceful in the air. In flight, the deep fork of the tail is clearly visible, especially against the sky.