Greatest recovery by a bird of prey species

The Mauritius kestrel (Falco punctatus), aka Crécerelle de Maurice, endemic to the Indian Ocean island of Mauritius, was almost wiped out of existence by the late 20th century. In 1974, there were just four known kestrels left in the wild (only one of which was a breeding female) and two in captivity. Based on the most recent assessment data (published in 2013), the population now stands at 350-500 individuals, 170-200 of which are mature birds. Although the status of the Mauritius kestrel was downgraded to Vulnerable by the International Union for Conservation of Nature (IUCN) in 2000, it has since been reclassified back to Endangered owing to a slight dip in numbers.

One of the leading causes of this falcon's decline was the drastic destruction of its native forest habitat from the early 17th century on, as a result of human colonization - first by the Dutch, then subsequently English and French settlers. By the 20th century, approximately only 2% of the island's original forest remained. This was exacerbated by the introduction of non-native species such as rats and cats that preyed on the birds' eggs and fledglings. The final hammer blow was the widespread use of the toxic pesticide DDT in the 1950s-60s to counter a malaria epidemic, with the chemical proving deadly not just to mosquitoes but much other Mauritian wildlife.

The success of this raptor's recovery lies largely down to the collaboration of multiple wildlife organizations, as well as (for the time) an unusual conservation approach of focusing on increasing the population size rather than purely restoring habitat. This was achieved through captive breeding, “cross-fostering” where the kestrels’ eggs and hatchlings were given to similar species to raise, and careful management of nestboxes and feeding stations in the wild.

Another bird species to have staged a remarkable comeback, thanks to considerable conservation efforts, is the Chatham Island robin (Petroica traversi), endemic to New Zealand's Chatham Islands in the South Pacific. In 1972, only 18 individuals could be found in the wild, dropping to seven by 1976 and a mere five by 1980. Of these five, there was only one female (named “Old Blue”) whose partner was a male called “Old Yellow”. As of the last census conducted in 2015, a total of 289 adult black robins were recorded.