Sunday, April 22, 2012

Getting rid of the Black Rats was really going to benefit the Sooty Terns, as mentioned below. But there were lots of other species that would benefit from the eradication. One of the targets was Audubon's Shearwater, a burrow nester like our own Manx Shearwater and therefore really vulnerable to predators such as rats. The Manx Shearwaters on Bardsey thrive because there are none of the rats which heavily impact on colonies elsewhere. Although they had never been recorded on Dog, a few Audubon's Shearwaters were nesting on nearby islands. It was thus hoped that they would soon colonise a rat free island when we'd done our job.

It was a massive surprise for us all when Rich stumbled across two pairs already nesting! Two streaks of crap led him to two cracks in a rock face, each containing an incubating adult. One of the nests also contained the remains of a hatched egg, suggesting that the bird was on a small chick. Unlike our Manx Shearwater, Audubon's are not thought to undertake a lengthy migration, but rather remain in the waters of the western Atlantic. The short-winged, long-tailed silhouette is obvious in this photo, as are the marked undertail coverts and relatively short, thin bill. (c) Richard Brown

It is not just birds that will benefit from the eradication. The Anguilla Bank Anole will also benefit hugely. These smart little anoles are endemic to the Caribbean Lesser Antilles. The brightly coloured dewlap is used both in courtship and when trying to ward off predators. It doesn't always work however. Following the link will bring up a photo of an anole failing spectacularly to startle a predator! (c) Richard Brown

One of the main predators of the Bank Anole is the American Kestrel. They don't hunt in the same way as our Kestrels, but rather perch until they spot their prey before flying directly at it. This bird is a female, lacking the blue-grey wing of the male. Females tend to winter in more open areas than the males, the preferred habitat for this species. The likely explanation is that the larger females arrive in prime areas first and then exclude any males which appear later. (c) Richard Brown

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