Larus belcheri
Silhouette: Juan Carlos Jerí · PhyloPic
In 3 days ~60% in a week ~90%
Belcher's gull (Larus belcheri), also known as the band-tailed gull, is a bird in the family Laridae found along the Pacific coast of South America. It formerly included the very similar Olrog's gull as a subspecies, but that bird occurs on the Atlantic coast of South America and is now accepted as a separate species Larus atlanticus. Belcher's gull is a medium-sized gull with a blackish mantle, white head and underparts, a black band on the otherwise white tail, and a yellow bill with a red and black tip. Non-breeding adults have a brownish-black head and a white eye-ring. The name commemorates the British explorer Sir Edward Belcher, who performed survey work on the Pacific coast of South America.
Belcher's gull is 48–54 centimetres (19–21 in), with a wingspan of about 120 cm (47 in). The sexes are similar in appearance, and in the breeding season, the adult has a white head, very pale grey neck, and white underparts. The mantle and back are greyish-black, and the tail is white with a broad black subterminal band and a white trailing edge. The wing coverts and primaries are black and the secondaries dark grey with white tips. The eye is black, the bill yellow with...
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Paracas National Reserve | 🇵🇪 Peru | |
| 2 | Pan de Azúcar National Park | 🇨🇱 Chile |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Lima | 🇵🇪 Peru |
Possible
About 30% of wildlife watchers report a Belcher's Gull sighting in Pan de Azúcar National Park on a given day, based on 19 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 11th most-seen of the 20 birds we can rate there. Over three days the chance rises to about 60%, and over a week to about 90%, if each day is a fresh chance.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Belcher's Gull sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Belcher's Gull sightings, Pan de Azúcar National Park ranks 2nd at about 30%. The best odds are in Paracas National Reserve (Peru, about 80%).
GBIF citizen-science records
It is estimated from how often the Belcher's Gull is recorded against all the birds logged in Pan de Azúcar National Park (19 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
