Richard Veit and Danielle Fibikar banding an Antillean cave bat. Photo William Stelzer
Once again, Richard Veit, a professor of biology
at the College of Staten Island in New York City, brought a group of college students
to St. John to examine the rich habitats surrounding the Virgin Islands
Environmental Resource Station (VIERS) in Lameshur Bay. The area seems to be full of
familiar wildlife (including over 60 types of birds), while also supporting
newcomers and at least one species thought to have disappeared.
I met Professor Veit and two of his graduate students last
April at VIERS and reported for the Tradewinds
on their respective research projects: Danielle Fibikar is working on documenting
the size and health of local bat populations, and Pearl Cales is studying different
types of frog vocalizations, while also identifying changes over time in their
density and distribution in certain areas of the island.
These researchers returned to St. John in November, and then
came back again in January to follow up on their subjects, while the
undergraduates in the Tropical Ecology Course were just getting familiar with
the different birds, lizards, and crabs around Lameshur.
My husband and I, and local photographer Bill Stelzer, were
excited take a trip out to VIERS and catch up with the research team to get an
update about their findings. We set out along the road by the beach at
Lameshur, where they set up fine-threaded ‘mist’ nets to catch bats flying
along the roadway after dark.
The first ones caught were fishing bats, Noctilio leporinus, out for dinner. One
of the fishing bats that got tangled up in the net had a familiar face – they
had caught him several times before, most recently just a few days before. It
was easy to tell because they put tiny metal tags on the wings of the bats
before releasing them. Their re-catch rate shows that there is a fairly stable
community of fishing bats in that area. The researchers also weigh and measure
the bats. The one caught a few days earlier hadn’t grown in such a short time
but turned out to be 8 grams heavier than before, probably because he had just
eaten a small fish that evening before flying into the net. These bats fly low
over the water in the dark using echolocation to locate little fish and grabbing
them with the sharp claws on their hind feet.
The other
bats caught that night were fruit-eating Antillian cave bats, Brachiphylla cavernarum, which seem to
be getting more numerous on St. John based on the recent mist net counts and an
examination of the buildings at the old Reef Bay sugar mill. These bats represented
less than 10 percent of the bats netted on St. John by the Island Resources
Foundation team in their 2009 survey (with Jamaican fruit bats, Artibeus jamaicensis, making up close to 75 percent of
the total). The cave bats have been listed as a species of ‘Greatest Concern’ on the Territory's
Endangered Species List, probably due to a limited number of caves for roosting
and a general loss of habitat. www.irf.org/documents/VI_Bat_C%20&_M_Plan_December%2009.pdf
The
researchers told us that one night they caught five different types of bats
within a few hours – including (besides the ones already mentioned) a
relatively common insect-eating velvety free-tailed bat, Molossus molossus, and a rare red fig-eating bat, Stenoderma rufum, which is only found in
Puerto Rico and the Virgin Islands, and is also listed as a species of Greatest Concern
on the Virgin Island’s Endangered Species List. During the Island Resources
Foundation three-year survey, there were only 15 of the red fig-eating bats caught
- out of 1,200 - slightly more than one percent of the total.
Caribbean White-lipped frog. Photo William Stelzer
Pearl is focusing part of her research on documenting the different sounds made by the white-lipped frogs. She is also doing a survey of overall frog sounds at selected points to see if there are any changes. Mostly she is concerned about whether there has been an invasion of large cane toads, which could potentially eat up many of the local tree frogs. This year, she did find one cane toad in Coral Bay on the flat land near the site of the Roller’s farm.
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Pearl Cales with cane toad.
As a bird lover, I was pretty excited to hear that Professor Veit had also identified a rare bird in the flat area near Coral Bay – a screech owl, Otus nudipes, that has been found only in Puerto Rico and the Virgin Islands. In 1995, these birds were declared extinct in the Virgin Islands because a careful survey of the three main islands (which have the woody habitats they require) had turned up no evidence of them. I thought I had heard an owl in the night recently, and wondered if it could have been this type. Although the recorded common cries of the screech owl didn’t exactly match up with the hooting sounds I remember hearing, these little owls do apparently make loud ‘coo-coo’ sounds - as a result of which they were given the name “Cuckoo-bird” in the Virgin Islands. www.oiseaux-birds.com/card-puerto-rican-screech-owl.html
Professor Veit also saw another unusual bird in the lagoon
near Lameshur Bay – a Little Egret. This bird is a Eurasian species that is in
the process of colonizing the western hemisphere. They first nested in
Barbados in 1994, where there are now 15-25 nesting pairs. That is still
the only western hemisphere breeding location, but they have been recorded on many
Caribbean islands including Puerto Rico, and have even been found as far north
as Newfoundland. It looks like a snowy egret, but has two distinctive thin
feathers at the back of its head.
In addition, he ran into four brightly colored Adelaide’s
warblers, which are generally found only in Puerto Rico, along the south shore
trail near VIERS. These sightings of rare birds were particularly interesting
to me, since I was asked to lead an early morning bird walk at Lameshur during
the Unitarian Universalist Fellowship retreat at VIERS. Meanwhile
I have been practicing trying to identify the different bird songs and frog
voices around my house.
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