The Banasura laughingthrush was described by zoologistEdward Blyth in 1851, based on a type specimen collected at Banasura Hill in modern-day Kerala by Thomas Jerdon. Blythe originally placed it in the genusGarrulax. After a period of taxonomic reorganization, the species, along with the Palani laughingthrush and the Ashambu laughingthrush, was placed in the genus Montecincla, in which it remains today. The Banasura laughingthrush was formerly treated as conspecific with the Nilgiri laughingthrush, and was known as the black-chinned laughingthrush. However, morphological and geographic analysis revealed that the Banasura and Nilgiri laughingthrushes were better treated as different species entirely, due to apparent allopatric speciation, and the Banasura laughingthrush was consequently awarded full species status in 2015. Later genetic analysis corroborated the validity of the split. The Banasura laughingthrush is genetically most closely related to the Nilgiri laughingthrush, and the two species are estimated to have diverged about 330,000 years before the present.
Description
The Banasura laughingthrush is a medium-sized songbird, ranging between 203 and 230 cm in length, and between 36 and 52 g in mass. Adults have a black face and throat; white supercilia; a gray breast, cheeks, and back; an ochre belly; and olive back, wings, and tail. Additionally, adults have a black bill, crimson irises, and brownish legs. It is distinguished from the Nilgiri laughingthrush by its gray breast, and from the Palani and Ashambu laughingthrushes by its black chin. The sexes are indistinguishable in plumage. While the Banasura laughingthrush is extremely similar in appearance to other species within Montecincla, it is the only species of its genus found within its range, making identification straightforward.
Distribution and habitat
The Banasura laughingthrush has an extremely restricted range. It is endemic to a small series of sky islands in the Western Ghats in South India, between the Brahmagiri Hills of Kodagu in the north and Vavul Mala in Kerala in the south. Within this range, fragmented populations are found at Banasura Hill in Wayanad, Chembra Peak, and Vellarimala. The Banasura laughingthrush is primarily found in shola habitat between 1,400 and 2,400 meters in elevation.
Behavior and ecology
The Banasura laughingthrush forages in the shola midstory and lower canopy by hopping among branches, feeding primarily on fruits and insects. Individual birds are fairly sedentary, and do not regularly travel between sholas. Like other Montecincla laughingthrushes, the Banasura laughingthrush is highly vocal. The most typical song type is a series of 3 to 6 loud, nasally whistles, but this song is highly variable, with various 2, 3, 4, and 6-note songs being well documented. While the Banasura laughingthrush's song cannot always be distinguished from that of the Nilgiri laughingthrush, analyses have shown the Banasura laughingthrush's song to be generally higher in complexity than any of the other Montecincla laughingthrushes.
Conservation
Due to its extremely small range of under 57 km², the population of the Banasura laughingthrush is estimated at only around 500-2,500 adults.The Banasura laughingthrush's range is also highly fragmented, rendering the species even more vulnerable to declines due to habitat loss and degradation. Due to its small population size and range, the species is ranked by the IUCN as Endangered. The Carmel Hump Mountains Important Bird Area was designated specifically to protect crucial habitat for the Banasura laughingthrush.
