Mauritius kestrel | |
---|---|
Ebony Forest, Mauritius | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Falconiformes |
Family: | Falconidae |
Genus: | Falco |
Species: | F. punctatus |
Binomial name | |
Falco punctatus Temminck, 1821 | |
The Mauritius kestrel (Falco punctatus) is a bird of prey from the family Falconidae endemic to the forests of Mauritius, where it is restricted to the southwestern plateau's forests, cliffs, and ravines. [3] It is the most distinct of the Indian Ocean kestrels. It colonized its island home to evolve into a distinct species probably during the Gelasian (Late Pliocene [4] ). It is the most distant living species among the western Indian Ocean kestrels. [5]
In 1974 the Mauritius kestrel was close to extinction, with only five or, possibly, six known birds of which two in captivity and a solitary breeding female. In 1985, numbers were estimated to have increased slightly in the wild, but it remained critically endangered at fewer than 15 individuals. [6]
After considerable pioneering conservation efforts by Carl G. Jones and Abdool Wahab Owadally the numbers had increased to circa 400 birds in 2019. This conservation achievement is regarded as one of the most successful and best documented bird restoration projects in the world. [7] It was proclaimed the national bird of Mauritius in March 2022 to mark the 30th anniversary of the Republic of Mauritius. [8]
It can reach a size between 26 and 30.5 cm (10.2 and 12.0 in). It weighs up to 250 g (8.8 oz). Males are slightly smaller than the females. Wingspan is approximately 45 cm (18 in) and the wings are rounded, unlike those of other falcons. [3] The lifespan is 15 years in captivity.
The Mauritius kestrel hunts by means of short, swift flights through forests. [3] It is carnivorous, eating geckos, dragonflies, cicadas, cockroaches, crickets, and small birds. [3]
In pre-colonial times, the population was estimated to be between 175 and 325 breeding pairs. This small population was most likely caused by deforestation in the 18th century and by cyclones. However, the most severe decline was in the 1950s and 1960s due to indiscriminate DDT use and invasive species like cats, mongooses, and crab-eating macaques which killed the kestrels and their eggs. What was probably this species' closest relative in Recent times, the Réunion kestrel, became extinct in the 1670s. [9]
The quasi-extinction of the kestrel was noted by Mauritian naturalists Jean Vinson and France Staub, and it came to the attention of the American falcon expert Tom Cade, who, in the early 1970s, corresponded with the Conservator of Forests Leo Edgerly and they explored the idea of saving the Mauritius kestrels. Tom Cade had recently learned how to breed falcons in captivity and had bred American Kestrels and felt that similar approaches could be used to breed Mauritius Kestrels, and then to release the birds to the wild to bolster the population. Working with international conservation organisations (World Wildlife Fund and the International Council for Bird Preservation) and with the Mauritius Forestry Department a conservation project was hatched for the Mauritius Kestrel in 1973. The initial work was done by one of Cade’s students, Stanley Temple, who studied them in the wild and started the captive breeding project. [10]
The recorded population subsequently dropped to an all-time low of only four individuals in the wild in 1974, and it was considered the rarest bird in the world. Stanley Temple from Cornell University studied this species for two years and the first attempt in 1973 to breed the birds in captivity failed because the hatchling died when the incubator had a breakdown. Though conservation measures were immediately undertaken with the help of a breeding program by the Jersey Zoo (now Durrell Wildlife Park), the efforts to rescue this species initially failed because the eggs were not fertile.
In 1979, a new attempt was undertaken. With the help of Gerald Durrell, the Welsh biologist Carl Jones established a wildlife sanctuary on Île aux Aigrettes. He climbed on the trees and removed the eggs from the nests. This time the eggs were fertile, and Jones was able to rear the hatchlings in incubators.
Manipulation of the nesting biology with captive American kestrels (Falco sparverius) had been shown to be successful in the U.S. whereby if first clutches were removed, the bird would usually lay a second clutch. This 'double clutching' had demonstrated that young from second clutches do not differ in size or survival rates from those of first clutches. [11] [12]
During the 1981/82 breeding season, Carl G. Jones and his team in Mauritius removed first clutches from wild kestrels for artificial incubation. In addition, Carl G. Jones supplemented their diet to enable the laying a new egg after the first one had been removed, thereby averting any negative impact on the wild population. [13]
Slowly the population increased, and during a census in 1984 50 individuals were estimated. Techniques for breeding, release, and "hacking" of young birds were improved, the captive breeding center becoming a pioneering research institution for tropical raptor and small falcon conservation. The captive breeding programme was scaled back in the early 1990s as a self-sustaining population was established. Since 1994, the programme serves only as a safeguard, should some catastrophe befall the wild population, and other rare endemics are now being cared for at the station (such as the pink pigeon or the Mauritius fody).
In 2005, there were at least 800 mature birds; the remaining habitat allows for an estimated carrying capacity of circa 50–150 more (BirdLife International 2006a,b). They occur in the remaining forests of the island, especially in the Black River Gorges region. The species was downlisted to vulnerable by the IUCN in 1994 as releases of captive-bred birds became unnecessary. Little conservation action was deemed necessary only two decades—in Mauritius kestrel terms, a long lifetime or maybe four to five generations—after the species had stood at the very brink of extinction. Today, apart from routine monitoring to be able to assist individual couples that fail to establish breeding territories for lack of nesting facilities—a major limiting factor, [14] the ongoing control of introduced predators is basically all that is being done to assist the species' survival. [15]
In 2014, the species was uplisted to endangered due to a decline in a once increasing population. It is believed that there are fewer than 400 mature birds alive in the wild.
While some apparent inbreeding depression was noted in the captive birds,[ citation needed ] it was certainly lower than might be expected given that the effective population size was maybe 5 individuals during the mid-1970s. It is known that several genetic lineages of Mauritius kestrels have disappeared entirely during the 20th century population decline.[ citation needed ] However, the debilitating effects of DDT accumulation on the birds' health, and not inbreeding, are considered to have been the major cause for the failure of Temple's breeding program.[ citation needed ]
The evolutionary history of the birds seems to hold clues as to why: [16] Mauritius is a volcanic island, and although the colonization of the island by kestrels cannot be dated with high precision, it was almost certainly some time before volcanic activity died down. The Mauritius kestrel population seems to have survived a prolonged period of volcanic activity, which must have kept the population small and fluctuating as habitat, food, and kestrels were destroyed by volcanic eruptions time and again. As near-panmictic conditions were sustained for many generations, alleles that might cause inbreeding depression were steadily removed by means of natural selection. The phenomenon that effective population sizes as low as 4–5 can be tolerated without pronounced inbreeding depression is also known from other small-island birds, such as Petroica traversi or the Laysan duck.
The classification as an endangered species is due to the same fact: on an island as small as Mauritius, chance events like volcanic eruptions (hardly likely in our time) or storms (common and possibly increasing in frequency and strength) can always wipe out major parts of a species' population. [17]
The peregrine falcon, also known simply as the peregrine, and historically as the duck hawk in North America, is a cosmopolitan bird of prey (raptor) in the family Falconidae. A large, crow-sized falcon, it has a blue-grey back, barred white underparts, and a black head. The peregrine is renowned for its speed. It can reach over 320 km/h (200 mph) during its characteristic hunting stoop, making it the fastest animal on the planet. According to a National Geographic TV program, the highest measured speed of a peregrine falcon is 389 km/h (242 mph). As is typical for bird-eating (avivore) raptors, peregrine falcons are sexually dimorphic, with females being considerably larger than males.
The Hawaiian crow or ʻalalā is a species of bird in the crow family, Corvidae, that is currently extinct in the wild, though reintroduction programs are underway. It is about the size of the carrion crow at 48–50 cm (19–20 in) in length, but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage and long, bristly throat feathers; the feet, legs, and bill are black. Today, the Hawaiian crow is considered the most endangered of the family Corvidae. They are recorded to have lived up to 18 years in the wild, and 28 years in captivity. Some Native Hawaiians consider the Hawaiian crow an ʻaumakua.
Jersey Zoo is a zoological park established in 1959 on the island of Jersey in the English Channel by naturalist and writer Gerald Durrell. It is operated by the Durrell Wildlife Conservation Trust. It has approximately 169,000 visitors per year.
The lesser kestrel is a small falcon. This species breeds from the Mediterranean across Afghanistan and Central Asia, to China and Mongolia. It is a summer migrant, wintering in Africa and Pakistan and sometimes even to India and Iraq. It is rare north of its breeding range, and declining in its European range. The genus name derives from Late Latin falx, falcis, a sickle, referencing the claws of the bird, and the species name commemorates the German naturalist Johann Friedrich Naumann.
The American kestrel, is the smallest and most common falcon in North America. Formerly called "sparrowhawk", a misnomer as it is a true falcon and is unrelated genetically to the Eurasian sparrowhawk, Accipiter nisus. It has a roughly two-to-one range in size over subspecies and sex, varying in size from about the weight of a blue jay to a mourning dove. It also ranges to South America and is a well-established species that has evolved into 17 subspecies adapted to different environments and habitats throughout the Americas. It exhibits sexual dimorphism in size and plumage, although both sexes have a rufous back with noticeable barring. Its plumage is colorful and attractive, and juveniles are similar in plumage to adults.
The nankeen kestrel, also known as the Australian kestrel, is a raptor native to Australia and New Guinea. It is one of the smallest falcons, and unlike many, does not rely on speed to catch its prey. Instead, it simply perches in an exposed position, but it also has a distinctive technique of hovering over crop and grasslands.
Spix's macaw, also known as the little blue macaw, is a macaw species that was endemic to Brazil. It is a member of tribe Arini in the subfamily Arinae, part of the family Psittacidae. It was first described by German naturalist Georg Marcgrave, when he was working in the State of Pernambuco, Brazil in 1638 and it is named for German naturalist Johann Baptist von Spix, who collected a specimen in 1819 on the bank of the Rio São Francisco in northeast Bahia in Brazil. This bird has been completely extirpated from its natural range, and following a several-year survey, the IUCN officially declared it extinct in the wild in 2019. However, after over 20 years of conservation efforts, 200 macaws have been bred from just two parent birds, and 52 individual birds have since been reintroduced into their natural environment in June 2022.
The Madagascar pochard or Madagascan pochard is an extremely rare diving duck of the genus Aythya. Thought to be extinct in the late 1990s, specimens of the species were rediscovered at Lake Matsaborimena near Bemanevika in Madagascar in 2006. By 2017, a captive breeding program had produced a population of around 90 individuals. The birds were reintroduced to the wild in December 2018.
Isolated on various islands around the Indian Ocean, kestrel populations evolved into different species, like Darwin's finches. Behaviour remains similar to other small species of Falco except on (originally) forested Mauritius where kestrels hunt arboreally more like hawks. Due to the scarcity of mammals on oceanic islands, several species have adopted a diet containing many Phelsuma and other geckos. The species can be distinguished by coloration, but all except the banded kestrel share rich brown wings with black spotting. Sexes are alike in color except in the spotted kestrel, where differences are minor. As usual in birds of prey, females are larger than males; considerably so in some of these species as this assists resource partitioning.
The Guam rail, known locally and in Chamorro as ko'ko', is a small, terrestrial bird endemic to Guam in the Rallidae family. They are one of the island's few remaining endemic bird species. The species became extinct in the wild in the early 1980s when biologists captured the remaining wild population to establish a breeding program. They have since been successfully introduced to the nearby Rota and Cocos islands. In 2019, they became the second bird species to be reclassified by the International Union for the Conservation of Nature from Extinct in the Wild to Critically Endangered.
The echo parakeet is a species of parrot endemic to the Mascarene Islands of Mauritius and formerly Réunion. It is the only living native parrot of the Mascarene Islands; all others have become extinct due to human activity. Two subspecies have been recognised, the extinct Réunion parakeet and the living echo parakeet, sometimes known as the Mauritius parakeet. The relationship between the two populations was historically unclear, but a 2015 DNA study determined them to be subspecies of the same species by comparing the DNA of echo parakeets with a single skin thought to be from a Réunion parakeet, but it has also been suggested they did not constitute different subspecies. As it was named first, the binomial name of the Réunion parakeet is used for the species; the Réunion subspecies thereby became P. eques eques, while the Mauritius subspecies became P. eques echo. Their closest relative was the extinct Newton's parakeet of Rodrigues, and the three are grouped among the subspecies of the rose-ringed parakeet of Asia and Africa.
The Mauritius fody is a rare species of bird in the weaver family. It is endemic to the island of Mauritius. It is classified by BirdLife International as being endangered. It is also on the United States' Endangered Species List with an endangered status.
The pink pigeon is a species of pigeon in the family Columbidae endemic to Mauritius. The pink pigeon nearly became extinct in the 1970s and the 1990s and is still very rare. It is the only Mascarene pigeon that has not become extinct. It was on the brink of extinction in 1991 when only 10 individuals remained, but its numbers have increased due to the efforts of the Durrell Wildlife Conservation Trust since 1977. While the population remains at below 500 birds as of 2011, the IUCN downlisted the species from Critically endangered to Endangered on the IUCN Red List in 2000, and then downlisted it again to Vulnerable in 2018.
Captive breeding, also known as captive propagation, is the process of keeping plants or animals in controlled environments, such as wildlife reserves, zoos, botanic gardens, and other conservation facilities. It is sometimes employed to help species that are being threatened by the effects of human activities such as climate change, habitat loss, fragmentation, overhunting or fishing, pollution, predation, disease, and parasitism.
The Mauritian Wildlife Foundation (MWF) is an independent, non-governmental, non-profit conservation agency working in Mauritius and the Outer Islands to save threatened endemic local flora and fauna.
The term kestrel is the common name given to several species of predatory birds from the falcon genus Falco. Kestrels are most easily distinguished by their typical hunting behaviour which is to hover at a height of around 10–20 metres (35–65 ft) over open country and swoop down on ground prey, usually small mammals, lizards or large insects, while other falcons are more adapted for active hunting during flight.
The Malagasy kestrel, also known as the Madagascar kestrel, Malagasy spotted kestrel, Newton's kestrel, Madagascar spotted kestrel, katiti (Creole) or hitsikitsika (Malagasy), is a small bird of prey of the genus Falco. It is named after British ornithologist Edward Newton. It occurs in two subspecies on Madagascar and at Aldabra. The race from Aldabra is also called Aldabra kestrel. Its closest living relative is the Seychelles kestrel; they were at one time considered conspecific. Their common ancestors appear to have diverged very recently, probably less than 1 million years ago during the Early or Middle Pleistocene. The Mauritius kestrel is more distantly related.(Groombridge et al. 2002)
Bird conservation is a field in the science of conservation biology related to threatened birds. Humans have had a profound effect on many bird species. Over one hundred species have gone extinct in historical times, although the most dramatic human-caused extinctions occurred in the Pacific Ocean as humans colonised the islands of Melanesia, Polynesia and Micronesia, during which an estimated 750–1,800 species of birds became extinct. According to Worldwatch Institute, many bird populations are currently declining worldwide, with 1,200 species facing extinction in the next century. The biggest cited reason surrounds habitat loss. Other threats include overhunting, accidental mortality due to structural collisions, long-line fishing bycatch, pollution, competition and predation by pet cats, oil spills and pesticide use and climate change. Governments, along with numerous conservation charities, work to protect birds in various ways, including legislation, preserving and restoring bird habitat, and establishing captive populations for reintroductions.
Leptodactylus fallax, commonly known as the mountain chicken or giant ditch frog, is a critically endangered species of frog that is native to the Caribbean islands of Dominica and Montserrat. The population declined by at least 80% from 1995 to 2004, with further significant declines later. A tiny wild population remains on Dominica where there are efforts to preserve it, but few or none survive in the wild on Montserrat and its survival now relies on a captive breeding project involving several zoos. The initial decline was linked to hunting for human consumption, along with habitat loss and natural disasters, but the most serious threat now appears to be the fungal disease chytridiomycosis, which was the primary cause of the most recent rapid decline. On Montserrat it is known as the mountain chicken, while on Dominica it is known as the crapaud, which is simply the French word for "toad".
Carl Gwynfe Jones, MBE is a Welsh conservation biologist, who has been employed by Durrell Wildlife Conservation Trust since 1985, and a founding member (1984) and current scientific director of Mauritian Wildlife Foundation (MWF). Additionally he is Chief Scientist at Durrell Wildlife Conservation Trust, and an honorary professor in ecology and conservation biology at the University of East Anglia. Often outspoken on the importance of knowing your species and using intuition, empathy and practical knowledge over dogmatic education, Jones is best known for his work in recovering the Mauritius kestrel from just four individuals in 1974, to an estimated 400. Working in the Mascarene Islands since 1979, Jones has led five successful bird restoration projects where the starting population has numbered less than 12 individuals; as a consequence Mauritius has averted more bird extinctions than any other country. Jones has pioneered the use of ecological or taxon replacements to fill the ecological roles of extinct animals and successfully restored levels of endemic vegetation to previously denuded islets. Jones' work has been highlighted in Douglas Adams and Mark Carwardine's 1990 radio documentary Last Chance to See, along with its accompanying book, as well as David Quammen's 1996 book The Song of the Dodo: Island Biogeography in an Age of Extinctions.
The Mauritius Kestrel (Falco punctatus) had been studied since early 1973 and its life history is now fairly well known. It is a distinctive island form, the males averaging 130–140g and the females 160–170g. There is no readily detectable difference between adults and immatures, as all have the female type plumage. The species has evolved in the evergreen sub-tropical forests of Mauritius and occupies a niche similar to that of an accipiter. In morphology and behaviour it also shows convergence with accipiters, with short rounded wings and a dashing hunting technique. Considerable attention has been focused on this kestrel because of its extreme rarity and apparent impending extinction. In 1974 the world population was stated to be only six individuals, including two in captivity. Since then the kestrel is thought to have increased slightly in the wild, but it still remains critically endangered at fewer than 15 individuals.
Following del Hoyo and Collar (2014), we recognize Reunion Kestrel Falco duboisi, with range 'Extinct. Formerly occurred on Réunion Island; may have survived until the 1670s' (Cowles 1994).
The great rarity of the kestrel was noted by Mauritian naturalists Jean Vinson and France Staub
During the 1981/82 breeding season, we removed first clutches of eggs from wild kestrels for artificial incubation.
Although at least 71% of ringed birds attempted to breed in their first year, only 38% of the nests of first-year females successfully fledged young, averaging 1.7 per successful nest. Older females fledged young from 64% of nests, fledging an average of 2.0 per successful nest.