Indian Ocean kestrels

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Indian Ocean kestrels
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Malagasy kestrel (Falco newtoni)
Scientific classification
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Falco (partim)
Species

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 (such as the common kestrel, Falco tinnunculus) 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.

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Species

Two subspecies of Malagasy kestrel , F. newtoni, are recognised, one on the main island of Madagascar and one on neighbouring Anjouan and Aldabra. It has adapted to human encroachment better than much of Madagascar's wildlife. Its diet is mainly lizards and insects. Confusingly it is sometimes referred to as the spotted kestrel, a name usually used for the Moluccan/Indonesian kestrel, while the Mauritius kestrel's scientific name literally means "spotted falcon/kestrel".

Its closest relative is the Seychelles kestrel , F. araea. Their ancestors diverged probably less than one million years ago (roughly around the early Ionian) [1] It is the smallest of all kestrels, otherwise similar to the Madagascar kestrel (and originally considered the same species). Its range is reduced to Mahé, with a few pairs on Silhouette Island, North Island and Praslin. Its diet is mainly lizards. [2] The species' status, as the following one's, is Vulnerable according to the IUCN.

The Mauritius kestrel , F. punctatus, is more distantly related to the preceding two, having diverged from ancestral Madagascar region kestrels some time in the Gelasian (Groombridge et al. 2002). It is found only on Mauritius. It usually snatches arboreal prey, typically geckos or small birds. Habitat loss and DDT poisoning pushed this species to the brink of extinction, down to possibly as few as six individuals (and an even smaller effective population size) in the mid 1970s. The conservation effort was initially unsuccessful but results improved when new approaches were tried by Carl Jones in 1979. Chicks hatched at a sanctuary run by Gerald Durrell were released to new areas, and the population has now almost reached the carrying capacity of the island; intensive conservation activity has ceased for some time, with the last captive bred birds released in 1994.

The Réunion kestrel , F. duboisi, is probably the latter species' closest known relative. It only inhabited the island of Réunion, but became extinct for reasons not entirely clear around 1700. It is only known from subfossil bones and one brief eyewitness report.

The banded kestrel , F. zoniventris, is also restricted to Madagascar and is less common than F. newtoni. It is found in more arid habitats. It appears to be closer to the mainland African "gray kestrels" Falco ardosiaceus and Falco dickinsoni .

The spotted kestrel , F. moluccensis, is endemic to Indonesia. The Nankeen kestrel, F. cenchroides, inhabits Australia and New Guinea. These seem to belong to a lineage much closer to the common kestrel (Groombridge et al. 2002).

Other species of Falco - for example, sooty falcon, Eleonora's falcon, and the peregrine falcon - occur as occasional visitors in the region during migration. These are generally larger and/or entirely differently colored birds.

Related Research Articles

<span class="mw-page-title-main">Common kestrel</span> Species of bird

The common kestrel is a bird of prey species belonging to the kestrel group of the falcon family Falconidae. It is also known as the European kestrel, Eurasian kestrel, or Old World kestrel. In the United Kingdom, where no other kestrel species commonly occurs, it is generally just called "kestrel".

<span class="mw-page-title-main">Falcon</span> Birds of prey in the genus Falco

Falcons are birds of prey in the genus Falco, which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene.

<span class="mw-page-title-main">Falconidae</span> Family of birds

The falcons and caracaras are around 60 species of diurnal birds of prey that make up the family Falconidae. The family is divided into three subfamilies, Herpetotherinae, which includes the laughing falcon and forest falcons, Polyborinae, which includes the caracaras, Spiziapteryx and Falconinae, the falcons and kestrels (Falco) and falconets (Microhierax).

<span class="mw-page-title-main">Merlin (bird)</span> Species of bird

The merlin is a small species of falcon from the Northern Hemisphere, with numerous subspecies throughout North America and Eurasia. A bird of prey once known colloquially as a pigeon hawk in North America, the merlin breeds in the northern Holarctic; some migrate to subtropical and northern tropical regions in winter. Males typically have wingspans of 53–58 centimetres (21–23 in), with females being slightly larger. They are swift fliers and skilled hunters who specialize in preying on small birds in the size range of sparrows to quail. The merlin has for centuries been well regarded as a falconry bird. In recent decades merlin populations in North America have been significantly increasing, with some merlins becoming so well adapted to city life that they forgo migration.

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<i>Phelsuma</i> Genus of lizards

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<span class="mw-page-title-main">Nankeen kestrel</span> Species of bird

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.

<span class="mw-page-title-main">Bat falcon</span> Species of bird

The bat falcon is a falcon that is a resident breeder in tropical Mexico, Central and South America, Trinidad. It was long known as Falco albigularis; the names Falco fusco-coerulescens or Falco fuscocaerulescens, long used for the aplomado falcon, are now believed to refer to the present species.

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<span class="mw-page-title-main">Seychelles kestrel</span> Species of bird

The Seychelles kestrel is a small bird of prey belonging to the genus Falco in the falcon family, Falconidae. It is endemic to the Seychelles Islands where it is the only breeding bird of prey. It is known in Seychellois Creole as the katiti after its loud, shrill call.

<span class="mw-page-title-main">Orange-breasted falcon</span> Species of bird

The Orange-breasted Falcon is a bird of the falcon family. It is probably closely related to and looks like a larger version of the bat falcon, with whom it can be easily mistaken. These two, in turn, are probably closest to the aplomado falcon and constitute a rather old American lineage of Falco.

<span class="mw-page-title-main">Kestrel</span> Small bird of prey of the falcon genus, Falco

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. Kestrels are notable for usually having mostly brown in their plumage.

<span class="mw-page-title-main">Hierofalcon</span> Subgenus of birds

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<i>Trochetia</i> Genus of flowering plants

Trochetia is a genus of flowering plants from the family Malvaceae. They are endemic to the Mascarene Islands.

The Réunion kestrel is an extinct bird of prey which belongs to the falcon family. It inhabited the Mascarene island of Réunion and was part of the Western Indian Ocean radiation of kestrels.

<span class="mw-page-title-main">Mauritius kestrel</span> Species of bird

The Mauritius kestrel 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. 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 . It is the most distant living species among the western Indian Ocean kestrels.

<span class="mw-page-title-main">Malagasy kestrel</span> Species of bird

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)

<span class="mw-page-title-main">Banded kestrel</span> Species of bird

The banded kestrel is a bird of prey belonging to the falcon family Falconidae. It is endemic to Madagascar and is also known as the Madagascar banded kestrel, barred kestrel or Madagascar barred kestrel. Its closest relatives are the grey kestrel and Dickinson's kestrel of mainland Africa and the three are sometimes placed in the subgenus Dissodectes.

The wildlife of Mauritius consists of its flora and fauna. Mauritius is located in the Indian Ocean to the east of Madagascar. Due to its isolation, it has a relatively low diversity of wildlife; however, a high proportion of these are endemic species occurring nowhere else in the world. Many of these are now threatened with extinction because of human activities including habitat destruction and the introduction of non-native species. Some have already become extinct, most famously the dodo which disappeared in the 17th century.

References

Footnotes

  1. See Groombridge et al. (2002) for thorough discussion.
  2. Skerrett, Adrian; Ian Bullock; Tony Disley (2001). Birds of Seychelles. London: Christopher Helm.