Puff-backed Bulbul Microtarsus eutilotus Scientific name definitions

20–22 cm; 30–43 g. A chunky, bicolored, relatively quiet bulbul with large bill, short crest often raised at shallow angle; feathers of lower back dense and elongated, sometimes raised into a “puff” and revealing blackish bases. Whole face, including ear-coverts and down to jaw level, is ashy gray; crown brown with grayish tinge, central feathering slightly elongated; upper neck to rump dark rich brown, feathers of lower back to rump dark sooty brown at base, rump feathers black laterally and across rear edge, these parts broadly tipped whitish; uppertail-coverts chestnut-brown; upperwing-coverts and tertials as mantle; secondaries, primary-coverts and primaries the same, except that inner webs are dark sooty brown and outer webs edged rufous-olive; tail dull chestnut-brown, outer feathers boldly tipped white on inner webs; whitish below, breast washed grayish, flanks ashy, lower belly and vent tinged light yellow; underwing creamy white, primary coverts sooty, carpal feathering buff-yellow, axillaries silky white; iris light red to crimson (variation age-related?); bill black; legs dark slaty gray. Sexes similar, female possibly with slightly less prominent white tail tips. Juvenile is like adult, but tail pale-fringed only, without white flashes.

Extreme southern Myanmar (southern Tenasserim), southern Thailand, Peninsular Malaysia, Sumatra, Bangka and Borneo.

Usually found in mature lowland broadleaf evergreen forest (often in lightly or heavily logged sites), and forest edges. Also in tall and stunted kerangas and fire padang, subcoastal peatswamp-forest, mature abandoned Albizia plantations, and tall secondary growth in vicinity of original forest. Most sightings from plains level and low slopes, except on Mt. Jerai (Kedah), in northwestern Peninsular Malaysia, where ascends to 1,200 m; highest record in Borneo from 1,300 m.

Feeds on berries and other fruits, also insects. The only specific foraging records are of visits to fig trees: banyans (Ficus benjamina or F. microcarpa) and 14 of 25 Ficus in study at Kerau (Peninsular Malaysia), with mean minimum-diameter fruit size 5.4–15.5 mm. Found in singles or pairs, feeding largely on berries. Forages in lower and middle strata and, less regularly, in canopy; most conspicuous at forest edge. Often visits fruiting trees and shrubs to glean fruits, regularly joining other bulbuls. Also gleans insects from foliage, and sometimes joins mixed-species foraging flocks.

Usually rather silent, but presence often revealed by a “whimsical trill” from high perch, difficult to describe but sounding like loud, rather high-pitched, slurred, quavering warble with first note more emphatic, “tchui’uui tch’i-iwi’iwi, iwu’iwi-u”, or “tch’uwi’i’iwi”; at its simplest can be transcribed as “celery-celery”, but many variants more complex, becoming soft, hurried yodel with numerous sliding pitch changes and long-vowel combinations, e.g., “cheeu cheeu eeraloo eeraloo” or “chiaee-ruraleeoo”. Songs usually descend distinctly in pitch and sound melancholic.

Breeds March–June in Borneo; recent fledgling found on 7th May in Peninsular Malaysia. Rump feathers raised and puffed out in display. One nest was a small neat cup placed 60 cm above ground in a spiny palm. Clutch two eggs; no information on incubation and nestling periods; fledglings fed by adults for at least 10 weeks.

Not globally threatened. Currently considered Near Threatened. Uncommon to locally fairly common. Extinct in Singapore since 1836 (although recent unconfirmed sightings in watershed forests there). Preference for plains-level forest places this bulbul at risk; it is more reliant on tall lowland forest than are most bulbuls, suggesting that it is far more susceptible to the catastrophic clearance of this habitat in the Sundaic region. Its population should be monitored accordingly. Occurs in a range of important protected areas, including Taman Negara National Park, in Peninsular Malaysia, and Tanjung Puting National Park, in Borneo (Kalimantan).