Barro Colorado — Landseed

Map key

Barro Colorado Nature Monument

Adjacent protected forest

Iconic wildlifetap a species ↗

Central American agouti

Ocelot

Mantled howler

White-faced capuchin

Geoffroy’s spider monkey

Brown-throated sloth

White-nosed coati

Collared peccary

Jamaican fruit bat

Fringe-lipped bat

Ocellated antbird

Leafcutter ant

Isthmus roads

Panama Canal Railway

Ranges are indicative — generated from a habitat rule in the literature, not sightings. Mammals span the whole monument; the spider monkey (reintroduced) and ocellated antbird are island-only.

Altitude bands · 26–171 m

Summit ridges140 m +

Island plateau100–140

Lower slopes60–100

Shoreline & drowned valleys26–60

Gatún Lake26 m

Bands are altitude, and here they are deliberately landforms rather than vegetation. The real division on this island is forest age — old growth of 500+ years on the south and west, 70–120 year secondary forest elsewhere — and age does not follow contours.

Barro Colorado Nature Monument

An island of 15.4 km² and five mainland peninsulas, in a lake that did not exist before 1914. The boundary drawn here is the Smithsonian’s own GIS layer, not OpenStreetMap: OSM maps the monument as a single smooth envelope wrapping the island, the peninsulas and the open water between them, enclosing 111.5 km² against roughly 54 km² of land. On a map whose whole subject is a shoreline, that envelope would have erased the point.

Area

54 km² STRI, published

Island

15.4 km² STRI GIS polygon

Parts

island + 5 peninsulas

Reserve

1923

Monument

1979

Elevation

30 – 171 m

Isolated in 1914 — the Chagres was dammed for the Panama Canal and the valley filled to 26.7 m, leaving a hilltop as an island

Smithsonian Tropical Research Institute — a biological reserve since 1923, and one of the longest continuously studied tropical forests anywhere

50-hectare Forest Dynamics Plot — every woody stem over 1 cm mapped and re-censused since 1980; the template for a worldwide plot network

Between 50 and 90 bird species originally recorded here have gone from the island — at least 70 of them from isolation itself rather than from the forest simply maturing.

Boundary and both area figures: Smithsonian Tropical Research Institute, Barro Colorado Nature Monument boundary layer (ArcGIS Feature Service), retrieved 2026-08-03. Note: STRI publishes 5,400 ha for the monument while the land polygons in its own GIS layer sum to 4,892 ha; the published figure is shown and the difference is recorded rather than reconciled, because it was not established which is which. Elevation range and forest ages: Key Biodiversity Areas factsheet 19309 (Angehr 2007). Bird losses: Willis 1974, Ecol. Monogr. 44:153–169; Robinson 1999, Conserv. Biol. 13:85–97. Lake level: Autoridad del Canal de Panamá. Every figure on this site, and every figure rejected, is in docs/research-record.json.