BirdLife International reports that the Bermuda Petral (or 'Cahow' as it is known locally) has returned to nesting grounds on Bermuda's Nonsuch Island for the first time in over 400 years. Nonsuch Island is a 14-acre island located in Castle Harbor, a natural harbor formed by St. David's Island and the main island of Bermuda. The whole of Nonsuch Island has been established as a wildlife sanctuary and today offers secure habitat for the endangered petrals.

The return of the Cahow to Nonsuch Island marks an important step in the ongoing effort to ensure a secure future for the endangered bird. A 2005 census of the Cahow population estimated that there were 250 individuals, an encouraging count considering the species had been presumed extinct for the greater part of three centuries.

The decline of the bird is thought to have occurred when feral pigs, dogs, cats and rats were introduced by European settlers in the region. Since the Cahow constructs nests on the ground in burrows, it was an easy target for the introduced predators. The Cahow also was subject to intra-specific competition for their nesting sites by the White-Tailed Tropicbirds (Phaethon aethereus). Ultimately, the dwindling Cahow population was forced to less suitable habitat where they remained undetected for hundreds of years.

Then in 1951, 18 pairs of the petrals were discovered living on a group of rocky islets in Castle Harbor and since that time efforts have been focused on increasing the population and restoring them to more suitable breeding grounds.

The Cahow is Bermuda's national bird. The name Cahow is derived from the bird's eerie cries that so haunted the early Eurpoean settlers who encountered the birds that they avoided settling on the islands for fear of the demons that resided there.

Find out more:

• Cahow Return to Nonsuch (The Royal Gazette)
• The Fight to Save the Cahow (Surbirds.com)
• BirdLife International 2006. Pterodroma cahow. IUCN 2007. 2007 IUCN Red List of Threatened Species. Accessed May 27, 2008.
• Murphy, C R and L S Mowbray, 1951. New Light on the Cahow, Pterodroma Cahow. Auk. 68:266-280.
• Bermuda Petrel Returns to Nonsuch Island After 400 Years (BirdLife International)

Photo © Jeremy Madeiros / BirdLife International.