Unicolored Thrush Turdus haplochrous Scientific name definitions

The Unicolored Thrush is known only from Bolivia, specifically only from a few specimens coming from eastern Santa Cruz department, so in the lowlands not highlands. It is a dull and as the name implies, not the most brightly patterned of birds. It is a warm brown colored thrush with little else that stands out. What does stand out is that it is nearly unknown, other than these specimens from Bolivia it is has not been known in life. Recently biologist and birding tour leader Dan Lane found this species at one site in eastern Bolivia. That specific region of Bolivia is not poorly known, and enough work has been done in areas where this thrush is at least potentially present that it does appear to be truly rare. Hopefully further work in the coming years will determine if this species is truly restricted in distribution, if it is of conservation concern, and specifically what has made it so difficult to find until now. Perhaps not a colorful looking bird, but it does have a colorful story, and hopefully one that will become brighter as we find out more about this lost species.

23–24 cm; 84 g. Plumage is olive-brown above , slightly paler below, with dark-streaked whitish throat; bill pale brownish-yellow; legs brown. Sexes similar. Juvenile undescribed.

N Bolivia (SE Beni, W Santa Cruz).

Little information. Song  a series of whistled phrases, similar to that of T. hauxwelli; rattles and squawking calls  .

Not globally threatened. Currently considered Near Threatened. Poorly known; apparently rare. Range appears to be very small and distribution patchy, although habitat extensive and under little threat. Depending on method of calculation and veracity of records, known range covers 192,000 km² BirdLife International (2015) Species factsheet: Turdus haplochrous. Downloaded from http://www.birdlife.org on 13/11/2015. or as little as 48,860 km² (2 Herzog, S. K., O. Maillard Z., D. Embert, P. Caballero, and D. Quiroga (2012). Range size estimates of Bolivian endemic bird species revisited: the importance of environmental data and national expert knowledge. Journal of Ornithology 153(4):1189–1202. Close ). Habit of remaining relatively silent in the dry season, when most observers visit, may lead to under-recording; true abundance may be more accurately assessed in the wet season, when birds are singing (3 Lane, D. F. (2014). New and noteworthy records of birds in Bolivia. Cotinga 36:56–67. Close ). Present in Beni Biosphere Reserve and Isiboro Sécure National Park. Effective management of these areas needs to be secured. Wet season surveys urgently needed.