8 Dec 2020

Latest research: hope for threatened island birds, vulture poison crisis

Join us for a bite-sized round-up of advances published in our journal Bird Conservation International. Highlights include a species that’s learning to live alongside humans, the positive impacts of protected areas, and the next urgent challenge…

San Cristóbal Mockingbird © Mike's Birds
San Cristóbal Mockingbird © Mike's Birds
By Jessica Law

San Cristóbal Mockingbird adapting to change

What do you do when humans invade your island and modify vast swathes of habitat? For the San Cristóbal Mockingbird Mimus melanotis (Endangered), the answer would appear to be “keep calm and carry on.” When surveying the highly degraded Galápagos island of San Cristóbal, researchers found this endemic bird species was far more widespread than previously thought, and seems to have had a stable population since the 1980s. Although the original vegetation had been degraded by grazing goats, human settlements and non-native plants and animals, it seems the mockingbird has been able to adapt and tolerate change better than some of its relatives on neighbouring islands. Local eyewitnesses also suggest that the Least Vermilion Flycatcher Pyrocephalus dubius (currently presumed Extinct) persisted until very recently – and may still survive somewhere on the island.

 

Peruvian Diving-petrel © Pablo Caceres Contreras / Flickr

Peruvian Diving-petrel in recovery

Great news for this Endangered seabird, which could soon see a return to its former glory thanks to protection of its island breeding grounds. The Peruvian Diving-petrel Pelecanoides garnotii used to have a large population of around 100,000 breeding pairs on offshore islands along the coasts of Peru and Chile. However, by the 1980s numbers had dwindled to a mere 1,000 pairs, its nesting sites invaded by guano miners, hunters and introduced predatory rats and dogs. In Chile, the bird now breeds on just five islands. Three of these are legally protected, but only two have management plans. In their survey, researchers found that the petrel’s Chilean population had experienced recent rapid growth and now numbers 12,500 breeding pairs, 95% of which were found on Choros Island, the only island with adequate protection. This study shows what can be achieved when seabirds are allowed to breed in peace and safety, and the importance of expanding this model to other islands.

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White-backed Vulture © Laszlo Csoma

African White-backed Vultures in poisoning crisis

The White-backed Vulture Gyps africanus is Critically Endangered, in large part due to poisoning across its range. Unlike Asian vultures, which are often poisoned accidentally, much of this poisoning is deliberate. For example, ivory poachers may douse elephant carcasses in pesticides to kill vultures that may otherwise gather around the remains and draw attention to their illegal activities. Other vultures are poisoned for the belief-based use of their body parts. Aerial surveys of the species in north-central Botswana showed that nesting numbers had declined by more than half between 2006 and 2017, and breeding success was also significantly lower in 2017 than it was ten years earlier. Projections suggest that if recent high poisoning rates continue, this population could be extirpated from the area in the next 13 years.

 

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