April 23, 2004 – It's nesting time for the Least tern, and one of the places on St. Croix where the hatchlings of this endangered species have the best chance of surviving is on the ground around the storage tanks of the Hovensa refinery.
In cooperation with environmental agencies, Hovensa personnel keep an eye out for nests and mark those they come upon with brightly colored tape to warn off other employees.
The birds nest in colonies, and they prefer open spaces, which makes the ground around the storage tanks attractive. They also like beaches, salt flats and other industrial areas around St. Croix, but in Hovensa's dog-free environment the young terns have a better chance of survival.
"They are very susceptible to dogs," Claudia D. Lombard, a biological technician with the U.S. Fish and Wildlife Service on St. Croix, said of the hatchlings. However, there is a fence around the refinery, and Hovensa personnel routinely trap dogs that even so find their way in.
Last year, other colonies around St. Croix were lost to dogs, Lombard said. One colony at Sandy Point that was fenced off after the Least terns laid their eggs, may have been destroyed by cats, she said, but dogs are the worst predators.
Hovensa's colonies of Least terns may have some of the highest reproductive rates on St. Croix. Lombard said a Fish and Wildlife Service survey done last year identified about 150 nests at the refinery during the breeding period, from May through July.
The species is on both the federal and territorial endangered lists.
Lombard said the migratory Least terns arrive in mid- to late-April and are now courting. "Breeding begins the first week in May," she said, and soon the females will make nests and lay their eggs.
Lombard said it's not known where the terns migrate from, and Fish and Wildlife officials are thinking about banding the birds to find out. "But it's a difficult thing to capture a large number of birds during the breeding season," she said.
The 2004 Fish and Wildlife survey at Hovensa just got under way, and researchers are monitoring the nesting areas twice a week through Aug. 20. Other Least tern surveys are in progress elsewhere around St. Croix. Lombard said the goal is to determine the reproductive success and long-term viability of Least terns on St. Croix.
The study is a collaborative project of the Fish and Wildlife Service, the Planning and Natural Resources Department's Fish and Wildlife division, and the cooperative fish and wildlife research unit of the U.S. Geological Survey at North Carolina State University.
Richard Smullen, Hovensa's vice president for environmental health and safety, said the birds usually nest "in depressions scraped in sand, shells or gravel near the sea where there is little or no vegetation." Flagging the nests on refinery property with colored tape "doesn't cause us a major disruption," he said.
Last year for the first time, according to a Hovensa release, the company distributed flyers to the employees explaining that the birds are endangered and that Hovensa is an important nesting ground for the species. The flyers asked everyone to stay clear of the marked nests — not only to avoid damaging the eggs but also to avoid causing the adult birds to abandon the nests, thus exposing their eggs to harm from the sun's rays.
Smullen said employees simply take a different route when walking or driving so as to avoid the nests.
Lombard wishes St. Croix residents would do the same at other Least tern nesting sites around the island. She said people often drive through dried-up salt ponds, which can crush the nests or send the adult birds packing, again exposing the eggs to the hot sun for an extended period.
Lombard said the Least tern is so named because it is the smallest of the terns. Its scientific name is Sterna antillarum. It weights less than an ounce and is about 9 inches long.
Smullen said that protecting the Least tern nests is in keeping with Hovensa's environmental ethic.
According to Cornell University's Laboratory of Ornithology, Least terns first became endangered in the United States in the late 1800s, when East Coast hunters pursued them for their popular plumes. Thanks to protective legislation, the species had recovered by the 1920s, the Hovensa release stated, but now the birds again are threatened because of loss of breeding habitat due to coastal area development and disruption of sites that have been turned into recreational areas.
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