Critically endangered seabirds unable to find mates

April 29th, 2008 - 4:08 pm ICT by admin  

Washington, April 29 (IANS) Alarmed by the probability that one of the world’s rarest seabirds might soon be extinct, scientists are creating a protected breeding colony to help them attract females. The rapidly dwindling species, Magenta Petrel, now has only between eight and 15 breeding pairs. Molecular analysis of the endangered species discovered that 95 percent of non-breeding adults were male, hence unable to attract a mate.

The Magenta Petrel was rediscovered in 1978 on Chatham Island, New Zealand, 111 years after it was first collected at sea. The species has dwindled by 80 percent over 45 years.

The primary cause is introduced species like pigs, cats and rodents - which prey on the petrels and compete for their nesting burrows, reports Sciencedaily.

Male and female Magenta Petrels are difficult to distinguish by sight alone. Scientists collected blood samples from almost the entire known living population over a 20-year period. This allowed the team to distinguish gender accurately using DNA sexing techniques.

The sex-ratio of males to females was approximately even in petrel chicks and breeding adults. However, 95 percent of non-breeding birds were found to be male. This finding suggests that unpaired males may be having difficulty in attracting females to burrows.

Conservationists are helping to increase the petrel’s density by focusing birds within the Sweetwater Secure Breeding Site, where chicks are being translocated. Adult petrels are also being attracted by use of bird calls.

Eight chicks were successfully moved and fledged last year, and The Chatham Island Taiko Trust was established in 1998 to provide legal status to the continuing work.

These findings were published in Birdlife International.

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