2012/13 Cahow Recovery Programme Report

December 29, 2013

The Department of Conservation Services has released its Cahow Recovery Program 2012-2013 Breeding Season Report, one of the many efforts made by the Department to educate the public on the steps being taken to protect the Cahow, given its critically endangered status.

The report’s executive summary says, “The Cahow Recovery Program is a long-term management, research and recovery program for Bermuda’s National Bird, the critically endangered Cahow, or Bermuda petrel.

“This program is focused on increasing the breeding population through the control or elimination of threats to the species, provision of additional artificial nesting burrows, and the establishment of entirely new nesting colonies.

Week old Cahow chick photographed on Nonsuch Island in March 2013 by Jeremy Madeiros:

cahowchick

“The Cahow nests only on the Islands of Bermuda and was thought to have originally numbered more than half a million birds, but was catastrophically affected by the arrival of humans on the island in the early 1600s.

“This was due both to direct hunting by the settlers and by invasive predators introduced by man, such as rats, cats, dogs and pigs.

“After less than 20 years of settlement, the Cahow by the 1620s had declined to the point where it was thought to be extinct, a belief that persisted for almost 350 years until the rediscovery in 1951 of a tiny remnant population on four tiny offshore islets.”

“Since 1960, a conservation and recovery program has been in place that has addressed and controlled most threats to the species. The program was administered by Dr. David Wingate until his retirement in 2000, since which it has been administered by the author of this report [Jeremy Madeiros, Senior Conservation Officer].

A look at week #4 of the “Cahow Cam” from LookBermuda

“The program has enabled the breeding population to begin a slow, but accelerating increase from only 18 pairs producing a combined eight chicks annually in the 1960s to a new record number of 105 breeding pairs in 2013, producing a total of 53 successfully fledged chicks.

“Increased knowledge and public interest in the Cahow has been brought about from several films, documentaries and books that have been completed highlighting the conservation and recovery work being carried out on the species.

“The main threats to the Cahow include the erosion and flooding of the present nesting islets by storm activity and continuing sea-level rise, predation by rats and other invasive species swimming to these islets, a lack of sufficient numbers of suitable nest burrows or rock crevices, and nest-site competition with the Longtail or White-tailed Tropicbird Phaethon lepturus catsbyii.

Some of the highlights for the 2013 Cahow nesting season include:

  • The new nesting colony of Cahows established on Nonsuch Island by the translocation of chicks between 2004 and 2008 continues to grow, with 12 pairs established in nest burrows and laying eggs. From these, five chicks hatched and successfully fledged out to sea. New pairs and prospecting activity was noted in two additional nests, and a total of 29 of the translocated birds have so far returned to Nonsuch as adults, in addition to three non-translocated Cahows attracted to the new colony by the returned translocated birds.
  • The total breeding population of the Cahow has reached 105 nesting pairs, numbers which almost certainly have not been seen since the early 1600s.
  • Despite the increase in the number of nesting pairs, the number of chicks that successfully fledged fell slightly to 53, compared to 57 during the 2011-2012 nesting season.
  • Despite the impact of hurricanes Raphael and Sandy in the fall of 2012, little damage and erosion to nesting burrows was recorded, and there appears to have been little effect on breeding success in the 2012-2013 breeding season.
  • The second translocation of Cahow chicks to Nonsuch was commenced at the “B” translocation site, on the south hill overlooking the south beach area of Nonsuch and approximately 200 metres east of the “A” colony site. A total of 14 Cahow chicks were translocated from the four original nesting islets to artificial nest burrows at the site and hand-fed on fresh anchovies and squid. 12 of these chicks fledged successfully out to sea.
  • The biggest surprise of the season was the discovery that Cahows have naturally colonized Southampton Island, located to the southwest of Nonsuch Island and only 80 metres from the largest present Cahow nesting colony on nearby Horn Rock. Three nesting pairs were discovered using deep rock crevices near the northern end of the island.
  • For the first time, an infrared “burrow cam,” developed by JP Rouja of LookTV, was installed in one of the Cahow nest burrows on Nonsuch Island and weekly video updates were posted on a website to allow school groups and the public to follow the development of a Cahow chick named Backson, from hatching to departure out to sea. It is hoped that online live-streaming will be possible by 2014.”

The full report from the Department of Conservation Services is below [PDF here]

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  1. street wise says:

    BRAVO! All associated with this essential programme, particularly Dr David Wingate and Jeremy Madeiros, are to be congratulated on their hard work, persistence, and wondrous success.