Hoopoe starling
The hoopoe starling, also known as the Réunion starling or Bourbon crested starling, is a species of starling that lived on the Mascarene island of Réunion and became extinct in the 1850s. Its closest relatives were the also-extinct Rodrigues starling and Mauritius starling from nearby islands, and the three apparently originated in south-east Asia. The bird was first mentioned during the 17th century and was long thought to be related to the hoopoe, from which its name is derived. Some affinities have been proposed, but it was confirmed as a starling in a DNA study.
The hoopoe starling was in length. Its plumage was primarily white and grey, with its back, wings and tail a darker brown and grey. It had a light, mobile crest, which curled forwards. The bird is thought to have been sexually dimorphic, with males larger and having more curved beaks. The juveniles were more brown than the adults. Little is known about hoopoe starling behaviour. Reportedly living in large flocks, it inhabited humid areas and marshes. The hoopoe starling was omnivorous, feeding on plant matter and insects. Its pelvis was robust, its feet and claws large, and its jaws strong, indicating that it foraged near the ground.
The birds were hunted by settlers on Réunion, who also kept them as pets. Nineteen specimens exist in museums around the world. The hoopoe starling was reported to be in decline by the early 19th century and was probably extinct before the 1860s. Several factors have been proposed, including competition and predation by introduced species, disease, deforestation, and persecution by humans, who hunted it for food and as an alleged crop pest.
Taxonomy
The first account thought to mention the hoopoe starling is a 1658 list of birds of Madagascar written by French governor Étienne de Flacourt. He mentioned a black-and-grey "tivouch" or hoopoe; later authors have wondered whether this referred to the hoopoe starling or the Madagascan subspecies of hoopoe, which resembles the Eurasian subspecies. The hoopoe starling was first noted on the Mascarene island of Réunion by Père Vachet in 1669, and first described in detail by French traveller Sieur Dubois's in 1674:Early settlers on Réunion referred to the bird as "huppe", because of the similarity of its crest and curved bill with that of the hoopoe. Little was recorded about the hoopoe starling during the next 100 years, but specimens began to be brought to Europe during the 18th century. The species was first scientifically described by French naturalist Philippe Guéneau de Montbeillard in the 1779 edition of French naturalist Comte de Buffon's Histoire Naturelle, and received its scientific name from Dutch naturalist Pieter Boddaert for the book's 1783 edition. Boddaert named the bird Upupa varia; its genus name is that of the hoopoe, and its specific name means "variegated", describing its black-and-white colour.
Boddaert provided Linnean binomial names for plates in Buffon's works, so the accompanying 1770s plate of the hoopoe starling by French engraver François-Nicolas Martinet is considered the holotype or type illustration. Though the plate may have been based on a specimen in the National Museum of Natural History in Paris, this is impossible to determine today; the Paris museum originally had five hoopoe starling skins, one was exchanged with the Swedish Museum of Natural History, Stockholm, and two have since disappeared. The possibly female specimen MNHN 2000-756, one of the most-illustrated skins, has an artificially trimmed crest resulting in an unnaturally semi-circular shape, unlike its appearance in life; the type illustration has a similarly shaped crest.
De Flacourt's "tivouch" led early writers to believe that variants of the bird were found on Madagascar and the Cape of Africa; they were thought to be hoopoes of the genus Upupa, which received names such as Upupa capensis and Upupa madagascariensis. Some authors also allied the bird with groups such as birds-of-paradise, bee-eaters, cowbirds, Icteridae, and choughs, resulting in its reassignment to other genera with new names, such as Coracia cristata and Pastor upupa. In 1831, French naturalist René-Primevère Lesson placed the bird in its own monotypic genus, Fregilipus, a composite of Upupa and Fregilus, the latter a defunct genus name of the chough. French naturalist Auguste Vinson established in 1868 that the bird was restricted to the island of Réunion and proposed a new binomial, Fregilupus borbonicus, referring to the former name of the island.
German ornithologist Hermann Schlegel first proposed in 1857 that the species belonged to the starling family,, reclassifying it as part of the genus Sturnus, S. capensis. This reclassification was observed by other authors; Swedish zoologist Carl Jakob Sundevall proposed the new genus name Lophopsarus in 1872, yet Fregilupus varius—the oldest name—remains the bird's binomial, and all other scientific names are synonyms. In 1874, after a detailed analysis of the only known skeleton, British zoologist James Murie agreed that it was a starling. English zoologist Richard Bowdler Sharpe said in 1890 that the hoopoe starling was similar to the starling genus Basilornis, but did not note any similarities other than their crests.
In 1941, American ornithologist Malcolm R. Miller found the bird's musculature similar to that of the common starling after he dissected a specimen preserved in spirits at the Cambridge Museum, but noted that the tissue was very degraded and the similarity did not necessarily confirm a relationship with starlings. In 1957, American ornithologist Andrew John Berger cast doubt on the bird's affinity with starlings because of subtle anatomical differences, after dissecting a spirit specimen at the American Museum of Natural History. Some authors proposed a relationship with vangas, but Japanese ornithologist Hiroyuki Morioka rejected this in 1996, after a comparative study of skulls.
File:Necropsar rodericanus.jpg|thumb|alt=|Subfossil bones of the related Rodrigues starling, described in 1879
In 1875, British ornithologist Alfred Newton attempted to identify a black-and-white bird mentioned in an 18th-century manuscript describing a marooned sailor's stay on the Mascarene island of Rodrigues in 1726–27, hypothesising that it was related to the hoopoe starling. Subfossil bones later found on Rodrigues were correlated with the bird in the manuscript; in 1879, these bones became the basis for a new species, Necropsar rodericanus, named by British ornithologists Albert Günther and Edward Newton. Günther and Newton found the Rodrigues bird closely related to the hoopoe starling, but kept it in a separate genus owing to "present ornithological practice". American ornithologist James Greenway suggested in 1967 that the Rodrigues starling belonged in the same genus as the hoopoe starling, owing to their close similarity. Subfossils found in 1974 confirmed that the Rodrigues bird was a distinct genus of starling; primarily, its stouter bill warrants generic separation from Fregilupus. In 2014, British palaeontologist Julian P. Hume described a new extinct species, the Mauritius starling, based on subfossils from Mauritius, which was closer to the Rodrigues starling than to the hoopoe starling in its skull, sternal, and humeral features.
Evolution
In 1943, American ornithologist Dean Amadon suggested that Sturnus-like species could have arrived in Africa and given rise to the wattled starling and the Mascarene starlings. According to Amadon, the Rodrigues and hoopoe starlings were related to Asiatic starlings—such as some Sturnus species—rather than to the glossy starlings of Africa and the Madagascar starling, based on their colouration.In 1999, the French palaeontologist Cécile Mourer-Chauviré and colleagues pointed out that Réunion is 3 million years old, which is enough time for new genera to evolve, but many endemics would have been wiped out by eruptions of the volcano Piton des Neiges between 300,000 and 180,000 years ago. Most recent and extant species would therefore probably be descendants of birds which had recolonised the island from Africa or Madagascar after this event. If the hoopoe starling had in fact evolved into a distinct genus on Réunion prior to the volcanic eruption, it would have been one of the few survivors of this extinction event.
A 2008 study by Italian zoologist Dario Zuccon and colleagues analysing the DNA of a variety of starlings confirmed that the hoopoe starling belonged in a clade of Southeast Asian starlings as an isolated lineage, with no close relatives. They used a toe-pad sample from the specimen in Stockholm. The following cladogram shows its position:
Zuccon and colleagues suggested that ancestors of the hoopoe starling reached Réunion from Southeast Asia by using island chains as "stepping stones" across the Indian Ocean, a scenario also suggested for other Mascarene birds. Its lineage diverged from that of other starlings four million years ago, so it may have first evolved on landmasses now partially submerged.
Extant relations, such as the Bali myna and the white-headed starling, have similarities in colouration and other features with the extinct Mascarene species. According to Hume, since the Rodrigues and Mauritius starlings seem morphologically closer to each other than to the hoopoe starling—which appears closer to Southeast Asian starlings—there may have been two separate migrations of starlings from Asia to the Mascarenes, with the hoopoe starling the latest arrival. Except for Madagascar, the Mascarenes were the only islands in the southwestern Indian Ocean with native starlings, probably because of their isolation, varied topography, and vegetation.
In 2024, French biologist Jérôme Fuchs and colleagues also studied the Stockholm sample, and confirmed the species' close relations with the starling genera Sturnia, Leucopsar, and Sturnornis. Their divergence estimate converged with the emergence of Réunion 2.1–3.0 million years ago, and did not indicate stepping stone dispersal. They also reconstructed the population history of the species, and found it went through a strong genetic bottleneck about 200–300.000 years ago before increasing during the last 10.000 years, though its population was not especially low compared to other extinct or critically endangered birds. The decrease in its population was perhaps due to a sea-level increase caused by the last interglacial period, which reduced the bird's habitat on the island.