Swallow-tailed Gull vs Andean Gull

In short

The Swallow-tailed Gull is easily distinguished by its deeply forked tail and nocturnal habits, while the Andean Gull is larger and typically found in highland regions. Both species share a similar gull-like appearance but differ significantly in behavior and habitat preferences.

Identification tips

• Tail shape: Look for the Swallow-tailed Gull's deeply forked tail.
• Size and bulk: The Andean Gull is noticeably larger and bulkier.
• Eye size: Swallow-tailed Gulls have larger eyes for nocturnal activity.
• Habitat: Swallow-tailed Gulls are coastal, while Andean Gulls are often in highlands or coastal in winter.

Size

The Andean Gull is larger and bulkier compared to the more slender Swallow-tailed Gull.

Plumage

The Swallow-tailed Gull has a distinctive forked tail and large eyes adapted for nocturnal vision. The Andean Gull, while larger, lacks the forked tail and has a more typical gull appearance.

Behaviour

Swallow-tailed Gulls are nocturnal foragers, unique among gulls, whereas Andean Gulls are diurnal. Swallow-tailed Gulls also breed asynchronously and do not return to their natal colonies.

Habitat

Swallow-tailed Gulls breed on the Galapagos Islands and off Colombia, foraging along the Pacific coast of South America. Andean Gulls are found in highland regions, descending to coastal areas in winter.