Volume XXIV No. 39 • Sept. 29, 2000

BHSU professor and students spend second summer in the Caribbean studying endangered snakes

Summer school in the Caribbean may be a great recruiting promotion, but for Dr. Brian Smith, biologist, and two Black Hills State students it was a tedious research project involving long hours, extremely hot temperatures, and days away from the comforts of home.

Smith and his student assistants spent two months this summer surveying the lizard populations on remote Caribbean islands near Antigua. Their research involved counting and surveying lizards, the primary food source of an endangered snake known as the Antiguan Racer (Alsophis antiguae). There are approximately 80 of the harmless snakes in existence at this time, 70 on Great Bird Island and 10 others reintroduced last fall to a smaller nearby island.

The recovery project is supported by the six-member Antiguan Racer Conservation Project (ARCP), a consortium which includes BHSU, and organizations from Britain, Antigua, and Washington, D.C.

The BHSU research group began its work last summer and will continue the research for at least three more years. They will be estimating the carrying capacity of the islands for the reintroduction of the Antiguan Racer to its former range. Smith will be conducting an annual census of the lizard and snake populations.

Before the snake can be reintroduced to an island, the island must have its rat and mongoose populations eradicated. These non-native mammals have decimated the snake population.

Smith said their lizard surveys produced no startling results this summer. They conducted 936 surveys. Most were done on four islands, but some initial survey work was done on two others.

"On Great Bird Island, there was a significant drop in lizard numbers at one habitat and on the other islands there were no changes except at one control site," said Smith. "Where the snakes were introduced, there were no changes in the lizard populations. The snakes showed no problems adjusting to the new habitat."

Smith speculated that a drop in the lizard population at a couple of the sites might have been the result of very dry weather this summer.

"One significant aspect we added to the project was a Global Positioning System (GPS) mapping unit into the field," said the BH herpetologist. "We can map the size of the island and the size of habitat. This helps to calculate the numbers of lizards on the island."

With snakes preying on lizards as their primary food, Smith was surprised to see a racer eating a baby bird (a nestling). He spotted the snake drop from about a meter above the ground with the bird. The island is forested with lots of vines so the snakes are able to work their way up the tree for a short distance.

"This activity had never been reported before," he said. "I immediately called the main island using my cell phone to report the sighting."

Smith said there was a large population of pigeons and doves nesting close to the ground on that particular island and the opportunity for a different food source was readily available. A colleague of his who has spent the past five years observing the snake had never witnessed them feeding on nestlings. The BH herpetologist spotted the unusual eating phenomenon on two separate occasions.

With the potential for an increased workload involving 1,400 to 1,500 surveys a summer during the next few years, Smith was pleased to be able to involve two BH students and one Caribbean student in this summerís survey work. The Caribbean student is working on a masterís degree supported by a scholarship from the United Kingdom. Smith plans to involve one or two additional BH students and a second Caribbean student in the project next summer. The Caribbeans will eventually oversee the reintroduction project.

A stable population of snakes is estimated to be 500. It will be some time before that number is reached. The first hatch from the ten recently reintroduced snakes is expected in late August or early September. Some of the small islands can only handle about 80 snakes, therefore more islands must be surveyed and prepared for reintroduction.

In the future, Smith hopes to find additional dollars to support more students in the research. He said they are considering snake reintroduction on a large privately owned island that could potentially handle a snake population of 300 to 400. That would be a big step toward reaching the minimum goal of 500 snakes necessary to stabilize the Antiguan Racer population and save it from extinction.

In the near future Smith and his student assistants will be analyzing the survey data and preparing for a return trip to the islands. Grants from the Columbus and Cleveland zoos have helped fund his research.