2025-2026 Project!

2025-2026 Future project. Conservation of the Dominica boa, Boa nebulosa.

Boa nebulosa is endemic to the lesser Antillean Island of Dominica, West Indies. The species is ecologically widespread throughout the Island, including coastal xeric and littoral woodland to montane rainforest. This species feeds on small to medium mammals, reptiles and birds. Conservation status: This species has been assessed as least concerned based on IUCN criteria. With its limited geographical distribution (790 km) Island could lead to a potential vulnerable status. Boas are killed for "medicinal oil" rendered from their fat, which is used as a local remedy for joint pain and possibly as an aphrodisiac.

Preliminary assessment. We will travel to Dominica in late April 2025 for two weeks and in fall of 2024. A preliminary assessment of boa habitat will be conducted by walking through accessible properties and noting and photographing potentially suitable boa habitat. Then priorities for surveys will be assigned based on accessibility and segments with the largest remaining continuous suitable habitat areas.

Dominica Field Research. Intensive visual encounter surveys (VES) will be conducted during the day. During each VES, team members will spread and walk slowly through the vegetation looking for boas in the entire visible surrounding habitats. Logs and rocks will be lifted, whenever possible, to search for boas and then replaced to minimize habitat disturbance. Trees, caves and vegetation will also be searched. Start and end locations of each VES will be recorded using a hand-held Global Positioning System (GPS). The number of people searching and the time searched will be recorded and will be taken into account for each VES to calculate an estimate of total search effort.

When Boas are encountered, they will be captured by hand and placed in a cloth snake bag for later processing. The GPS coordinate of each capture will be recorded and marked with brightly colored flagging tape to ensure the snake is released at the exact point of capture after processing. Data regarding the surrounding habitat, weather, time, and the behavior of the snake will be recorded on a data sheet at every capture. At the end of each VES, all snakes captured will be taken to a designated field station for processing.

Snake Processing. In the field station all snakes will be sexed, measured and weighed, and checked to see if they had been caught previously by scanning for the presence of a Passive Integrated Transponder (PIT) tag. Sex will be determined by the presence of enlarged anal spurs in males compared to the relatively discrete anal spurs in females. Where this difference is less obvious (for example, in smaller specimens) and sex cannot be determined, gender will be determined by probing retracted hemipenes. If the snake has not been previously caught, it will be injected subcutaneously with a PIT tag to facilitate identification if recaptured later. We will attempt to return captured snakes to their original site within 24-48 hours.

Radiotelemetry. Adult and sub-adult boas (up to four boas of each age class per island) caught will be surgically implanted with temperature sensitive radio transmitters (Model SB-2T; Holohil systems Ltd.) according to a modified version of the procedure reported by Reinert and Cundall (1982). The transmitters will weigh no more than 10% of the total body mass of the snake. This adheres to the guidelines set out by the American Society of Ichthyologists and Herpetologists (ASIH). Snakes will be allowed at least 24 hours to recover from surgery prior to their release. Once released, the snakes will be tracked every day for approximately two weeks using a Yaesu VR-500 receiver (100 kHz1300MHz) and a two-element “H” type antenna (Telonics, Inc., Mesa, AZ).

Dominica, island country of the Lesser Antilles in the eastern Caribbean Sea. It lies between the French islands of Guadeloupe and Marie-Galante to the north and Martinique to the south. The country has been a member of the Commonwealth since independence in 1978.

Dominica

The island is 29 miles (47 km) long and has a maximum breadth of 16 miles (26 km). The capital and chief port is Roseau. Dominica’s great natural beauty, especially its spectacular mountainous topography, has impressed generations of nature lovers.

The island is of volcanic formation. Dominica has a number of active volcanoes, although eruptions are rare. Other signs of geothermal activity include fumaroles (volcanic vents) and hot springs. In the south, Boiling Lake lies 2,300 feet (700 metres) above sea level; its waters are often forced 3 feet (1 metre) above normal by the pressure of escaping gases. The island has rich alluvial and volcanic soils. There are numerous rivers, all of them unnavigable. A range of high forest-clad mountains runs north to south, broken in the centre by a plain drained by the Layou River, which flows to the west; the highest points are Mount Diablotins (4,747 feet [1,447 metres]) and Mount Trois Pitons (4,670 feet [1,424 metres]). 

Young boa photographed on the Island of Dominica. Photographed by Ricky Lockett.

Dominica has a pleasant climate, particularly during the cooler months from December to March. Summer temperatures reach an average high of 90 °F (32 °C). Winter temperatures are not much lower, the average high being anywhere from 84 to 86 °F (29 to 30 °C). The dry season is from February to May, and the rainy season is from June to October, the most likely period for hurricanes (tropical cyclones). Rainfall varies, being especially heavy in the mountainous interior. Average annual coastal rainfall varies from about 60 inches (1,500 mm) to 145 inches (3,700 mm), but in the mountains average rainfall can reach 250 inches (6,350 mm). Dominica is the most heavily forested island of the Lesser Antilles. The forest is the habitat of a considerable variety of birds and animals. Two parrots—the imperial parrot, or sisserou (Amazona imperialis), and the smaller red-necked parrot (Amazona arausiaca)—are found only in Dominica. There are many hummingbirds, of which the blue-headed (Cyanophaia bicolor) is native only to Dominica and the neighbouring island of Martinique. The large frog known as crapaud or mountain chicken (Leptodactylus fallax), one of four amphibian species on the island, was long an emblematic part of Dominica’s fauna (and a national dish), but it has become highly endangered because of a fungal disease. (Britannica, 2023)