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Half Moon Caye National Monument


Half Moon Caye is located at the southeast corner of Lighthouse Reef, the eastern most of the three atolls in Belizean water, some 50 miles southeast of Belize City . The caye rise to eight feet above sea level and is approximately 45 acres (18.2ha) in size. The protected area includes all of the caye and a large portion of the surrounding fringing reef and lagoon. Lighthouse Reef is one of the few true coral atolls in the Caribbean.


The Half Moon Caye Natural Monument was created in March 1982- the first reserve to be created under the National Parks System Act of 1981. Prior to that, it became Belize's first protected area in 1928. At that time, an area of 14 acres, was designated a Crown Reserve. Protection of the Booby colony was the primary reason for this action. In 1996, UNESCO's World Heritage Committee formally adopted the Belize Barrier Reef Reserve System as a World Heritage Site. Seven marine protected areas along the Barrier Reef and its adjacent atolls comprises this World-Heritage reserve system. Both Half Moon Caye and Blue Hole Natural Monuments are part of this system of outstanding universal importance.

The establishment of Half Moon Caye Natural Monument was seen as a significant commitment to the environment by a country, which had only established its independence in September 1981. By this declaration, Half Moon Caye was the first protected area in Belize and the first marine protected area in Central America.

The Caye is divided into Two Very Distinct Ecosystems

The western region, with its dense vegetation, has correspondingly rich soil made fertile by guano from the thousands of sea birds nesting in this area. The eastern half of the caye is composed primarily of coconut palms with sparse vegetation below. Half Moon Caye is a sand caye formed by the accretion of fragments of coral, shells and calcareous algae broken down by continuous wave action. In some areas the seawater and calcium carbonate chemically bind, forming flat bedrock cliffs and tide pools. The dry, low quality sand limits the plant life suitable for such a distinct environment.

The atoll is an asymmetric rimmed platform, entirely surrounded by a fringing reef rising virtually to the surface. Inside this fringing reef is a lagoon with water depths ranging from 3 to 8 meters, speckled with hundreds of coral patch reefs rising near the surface. Seaward of the fringing reef, the bottom slopes gently to a precipitous “wall” which plunges sharply to great depths (more than 457 meters in most places). These exquisite walls are unparalleled anywhere else in the world and provide a unique diving opportunity.

When standing on top of the highest ridge on the caye, looking south, the submerged crescent or “half moon” shaped south beach can be seen (otherwise it remains out of sight).


One of Half Moon Caye's principal inhabitants is the Red-footed Booby (Sula sula) with a population around 4,000 breeding birds. This booby is one of the main reasons the natural monument was created. The adult booby population of this caye is unusual by having an almost total predominance (98%) of the white colour phase. The only other similar booby colony is on an island near Tobago. Elsewhere, adult Red-footed Boobies are dull brown.

The boobies live on the caye for nearly ten months, returning to refurbish the nests from the previous year in late November. Eggs are primarily laid in December and incubated by both parents for roughly seven weeks. The young remain in the nest until about July.

The boobies co-exist with their pirate neighbours, the Magnificent Frigatebird, that have a seven-foot wing span. The Frigatebird, a poor diver that cannot land on water, harasses the Booby when it has returned from a day of fishing and robs the Booby of its food. It is this behaviour, which is depicted on the BAS logo.

Some 98 other species of bird have been recorded on the caye; 77 of these are migrants. 17 of the migratory species were recorded regularly enough to indicate that they winter on or near the caye. Ospreys, Mangrove Warblers, and White-Crowned Pigeons are among the caye's regulars. One of the most popular visitor sites on the caye is the bird observation deck.


Three prominent members of the lizard family live on Half Moon Caye. These include the Green Iguana (Iguana iguana rhinolopha) which is locally called “bamboo chicken”. It may have been introduced as a food source, perhaps by British privateers in the 1800's, to be utilized by passing ships.. The Wish Willy (Ctenosaura similes), slightly smaller than the Iguana, grows to lengths of 3-4 feet. It is a drab yellow with black bars on its back. The Allison's Anole (Anolis allisoni) are common on Half-Moon Cay where the preferred habitat appears to be the crowns of coconut palms. Island Leaf-toed
Geckos (Phyllodactylus insularis) are common on Lighthouse Atoll beneath rocks and woody debris, and in coconut palms

Loggerhead turtles (Caretta caretta) and Hawksbill turtles (Eretomochelys imbricata), both listed as internationally endangered species, come ashore to lay their eggs on the sandy southern beaches. The hawksbill is exploited for its shell from which ornaments, jewellery and other items are made. Both the loggerhead and the hawksbill are still sought for their meat.

Other Wildlife

Though birds and reptiles make up a large portion of the wildlife found on Half Moon Caye, other species including the nuisance black rat (Rattus rattus), which feeds on booby eggs and coconuts, can be found there. An eradication program is currently underway to rid the caye of this introduced species, which also preys on lizards, small mammals, large insects, land mollusks, plant seeds and seedlings.


The caye is a typical littoral, climax forest in Belize . The orange flowered Ziricote (Cordia sebestena) is the climax species, with the red-barked Gumbo Limbo (Bursera simaruba), fig trees (Ficus) and tangle-foot vine (Capparis flexuosa) intermingled with other low trees. The littoral fringe is dominated by silver-grey Tournefortia bushes and white-flowered Spider Lily (Hymenocallis littoralis). Coconut palms dominate the eastern side of the caye.

Sea Life

Surrounding Half Moon Caye are waters teeming with marine life. From the shallow lagoon area to the southeast buttress formations, many marine species can be observed. The Lighthouse Reef is also home to the “Blue Hole” studied by Jacques Cousteau in recent years. This underwater cave, formed during periods of lower sea level, is a karst-eroded sinkhole where depths exceed 400 feet. It contains pleistocene stalactites and stalagmites and serves as an important habitat for shrimp and jewfish. The Blue Hole was designated a Natural Monument in 1996. And is also managed by the Belize Audubon Society.


The lighthouse, situated on the tapering eastern side, was first built in 1820. It was later replaced by another, that bears the inscription, “Completed December 1848. J.Grant, Builder”. The present steel-framed tower was added to the brick base and completed in 1931. Today the lighthouse is solar powered.

Caye Access

A dock with a pier head depth about 6 feet as well as an area for landing amphibious aircraft is located on the north side of the island. Chartered boat access is the most popular means of access as there is no regular air or boat service. Local live-aboard dive boats are now required to anchor in designated areas as their anchors have caused irreversible damage to the reef.

There is a visitor center, where visitors register, pay the park fee, and receive a map and information of the area. There is also a picnic area and a campsite.