Mystery Bird of Borneo

Tuesday, May 27, 2025

Mystery Bird of Borneo

Today’s special animal friend is the bristlehead, Pityriasis gymnocephala, the only bird endemic to (found only in) Borneo, which has loads of other bird species that aren’t endemic. Also known as the bristled shrike, bald-headed crow, or bald-headed wood-shrike, this passerine bird, about 9” high, lives in forest canopies in a variety of habitats in Borneo. Here’s a fancy place to stay if you’d like to try to see one:

They prefer lowland forests, but they have been observed at elevations up to 3,900 feet. The bristlehead has mostly black feathers, with bright red face, neck, and shoulders, and a stubbly-looking patch, sometimes yellow, on top of the head.

Bristleheads are carnivorous, using their heavy, hooked bill to catch lizards and frogs from tree trunks or branches, as well as picking up insects and spiders from the leaves or from deep in the bark. They are sociable in groups of ten or so, often flocking with other large forest birds such as cuckoos, babblers, and hornbills.

They are described as “slow and heavy” in flight, and their calls are said to be “noisy and untuneful.” I agree.

No breeding behavior of this species has been observed. There is video of one with what seems to be nesting material in its bill. Also, females have been observed with food, implying they might have been feeding chicks. One egg was found in a dead, female specimen. I think it’s interesting that so little is known about this.

The bristlehead is rated Vulnerable by IUCN. They are found widely across Borneo in both primary and second-growth forests, including swamp, mangrove, and dipterocarp forests. “Dipterocarpaceae is a family of flowering plants with 22 genera and about 695 known species of mainly lowland tropical forest trees. Their distribution is pantropical, from northern South America to Africa, the Seychelles, India, Indochina, Indonesia, Malaysia and Philippines. The greatest diversity of Dipterocarpaceae occurs in Borneo.”

Population density is usually low, but they are locally common in a few habitats. The main threat to the population is habitat loss. Lowland forests in Borneo are being cleared at an estimated rate of 2.5% per year, and illegal logging occurs in protected areas.