Good news for the Bermuda Petrel (Cahow)

An important step in the conservation of any endangered species is to expand the breeding range beyond a single site to lessen the impact of infectious disease or natural disaster. Case in point is the Endangered Bermuda Petrel (Pterodroma cahow), which up till now only nested on some small islets in Bermuda's Castle Harbour. These sites are considered suboptimal and at significant risk of flooding or erosion. This worry was brought home by Hurricane Fabian, which washed away large sections of the islets in September 2003. After decades of work by local conservation groups led by Dr. David Wingate (Bermuda’s former Conservation Officer), the habitat on nearby Nonsuch Island (32.3472°, -64.6643°) has been restored to something resembling its original state and more recently, some 81 Bermuda Petrel chicks translocated to the island. Nonsuch lies at the eastern entrance to Castle Harbour and is a protected wildlife sanctuary with restricted access to the public. In March 2008, it was announced by Birdlife International that 3 of these transplants had returned as adults and were observed entering artificial nesting burrows. Current reintroduction work is spearheaded by Jeremy Madeiros (Bermuda’s Department of Conservation Services and head of the Cahow Recovery Program) and Nick Carlile, an Australian scientist from the NSW Department of Environment and Conservation. Carlile and Dr. David Priddel devised the very successful Gould's Petrel (Pterodroma leucoptera) recovery program on Cabbage Tree Island, near Port Stephens, NSW. The total population of Bermuda Petrel is now in excess of 250 individuals. In addition to the ever-present threat of major storms and rising sea levels, invasive mammals such as rats can find their way onto the nesting islets, potentially devastating the breeding population.

Prior to European settlement of this remote archipelago, Bermuda Petrels nested all across Bermuda but were quickly extripated by introduced pigs and other mammals. They were thought to be extinct as early as 1620 until 1951 when 18 nesting pairs were discovered in Castle Harbour. Much remains to be learned about the natural history of these gadfly petrels, for example, very little is known about their feeding grounds. One or two birds are seen annually by pelagic excursions into the Gulf Stream off North Carolina and the presumption is that the majority of Bermuda Petrels disperse north of Bermuda. The use of satellite telemetry or isotope analysis might be one way to shed light on this.