Formerly the rarest raptor in the world, the Mauritius kestrel, Falco punctatus, is a small chestnut and white falcon measuring 20 to 26 centimeters. Its upper parts are rich warm brown to chestnut, with black markings on its wings and mantle while its underparts are white with black heart-shaped marks. Its short, rounded and broad wings are thought to enhance its manoeuvrability in the forest. Males are smaller than females.
The Mauritius kestrel’s original habitat is in primary native forests at all elevations. Captive-bred birds have been able to adapt to degraded and open areas, as they are able to exploit grasslands. The kestrel’s primary and historical source of food has been the Phelsuma day geckos which represents 82% of its diet, small reptiles, small birds, insects and introduced mammals such as mice and shrews. Mauritius kestrels are territorial, and pairs can stay together for several years, separating only if breeding fails. They nest in volcanic rock cavities, tree holes and nest boxes, where they usually lay 3-4 eggs. They have been observed to nest in suburban areas.
Due to the declining trend of the population, the species was downgraded from ‘Vulnerable’ to ‘Endangered’ in 2014 on the IUCN Red List of Threatened Species.
Declining and degraded habitats have led it to near extinction with just four wild birds left in 1974, before an intensive captive breeding and reintroduction programme led to its gradual recovery. However, recent trends indicate that its population may be declining again. Historical deforestation leading to habitat loss led to initial declines and was compounded by DDT pesticide use in the 1950s and 1960s, which was used in agriculture and for mosquito control. Introduction of animals such as rats, macaques, mongooses and feral cats are predators of the eggs, young and occasionally adults. Exotic trees and plants such as the traveller’s palm and strawberry guava have affected the habitat quality and are believed to reduce the kestrel’s hunting efficiency. The lack of adequate nest cavities in suboptimal habitats, in addition to the loss of genetic variation with high rates of inbreeding affect the long-term viability of the population. It is suspected that climate change may also be affecting the bird’s breeding season, with more wet days at the start of the season delaying laying date.
A recovery programme was initiated in 1973, followed by an intensive management programme from the early 1980s to bring the species back from the brink of extinction. Captive propagation and restocking, supplementary feeding, nest-sites enhancement and provision of nest boxes, control of predators around nests and release sites, manipulation of clutches and brood, and control and treatment of parasites are some of the measures that were taken. Captive bred birds when released have been observed to have the same survival rate as wild ones. The last captive bred release of birds took place in 1994 with diminished active conservation management. The population in 2011-2012 was estimated to be 300 to 400 individuals.
The restoration of the Mauritius Kestrel from the brink of extinction in the 1970s to around 800 individuals today is one of the greatest conservation success in history.