The grey-headed bulbul (Pycnonotus priocephalus) is a member of the bulbul family, Pycnonotidae. It is endemic to the Western Ghats in south-western India, and found from Goa south to Tamil Nadu at altitudes up to 1200m. It is found in dense reeds or thickets mainly near rivers and swampy areas inside forests. They have a distinctive call that reveals their presence inside dense vegetation where they are hard to spot. Their taxonomic position within the bulbuls is not clear.
Taxonomy and systematics
The grey-headed bulbul was originally described by Thomas Jerdon under the name of Brachypus priocephalus but was then "emended" in error by Edward Blyth to Brachypodius poiocephalus and the confusion carried forward in literature. Formerly, some authorities placed this species within the genus Ixos.
The genus Pycnonotus as currently defined has been identified as polyphyletic and the genus placement for this species may change in the future. This species has not been used in recent molecular phylogeny studies of the group.
The common name 'grey-headed bulbul' is also used as an alternate name for the yellow-bellied bulbul.
This bulbul is resident in moist broad-leaved evergreen forest with bamboo and dense undergrowth. Its plumage is olive-green, with a medium-grey on the crown head, nape and throat. The forehead is yellow-green. The back, wings are olive green becoming lighter towards the vent. The rump has yellowing green feathers edged in black giving a barred appearance. The flanks are dark and grey edged. The undertail coverts are gray. The beak is greenish and grey while the legs are pinkish yellow. The iris is distinctly bluish white. The tail is grey on the central feathers (the shaft being black), the outer ones are black and are broadly tipped with grey. Both sexes are similar but juveniles have the head dark olive with the yellow on the forehead duller. (Length 143-152mm; head 33-35mm; tail 74-77mm) The call is a sharp chraink. The call is distinct in having a single syllable unlike those of the core genus Pycnonotus members.
Behaviour and ecology
Found singly or in small groups, Grey-headed bulbuls actively join mixed-species foraging flocks during the non-breeding season.
Grey-headed bulbuls breed from January to June with a peak in April. The nest is a typical platform placed inside a low bush. They build their nest over a period of a week using vines, grasses or leaves. Many nests in a study in the Silent Valley National park were found to be made on saplings of Syzygium species or in reeds of Ochlandra travancorica. The typical clutch is one egg or sometimes two eggs that are incubated for 12 to 14 days. Eggs are sometimes destroyed and eaten by palm squirrels (Funambulus tristriatus). The eggs are pale pink to lavender and flecked in red, more densely on the broad end. Both parents take part in incubation and feeding. The nestlings leave the nest after 11 to 13 days.
The diet consists mainly of fruits (>65%) and invertebrates (>30%). Fruits include those of Symplocos cochinchinensis, Antidesma menasu, Clerodendrum viscosum, Syzygium cumini, Litsea floribunda, Maesa indica, Callicarpa tomentosa, Leea indica and Lantana camara.
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