The Halmahera Swiftlet is a small swiftlet about 10 cm long. It uses forest and dense vegetation and feeds on small invertebrates.
It is about 10 cm long. The species account used here supports its small size but does not provide a plumage detail for this description.
It occurs in forest and dense vegetation and feeds on invertebrates.
During a July–August 2012 survey on Obi, dark swiftlets were often seen flying high above the canopy. The white-rumped form was the least common and was usually seen in flocks of 10–30, alone or mixed with other species. The authors said this form fitted the previous identification as ceramensis while also noting that swiftlets on the island are difficult to identify.
Field notes from the late-2013 and early-2014 expedition report the form as common above Sumber Agung near Gunung Tumpu in eastern Sulawesi. They describe an electric buzzing call and an obvious pale rump. The account gives no feeding or nesting observations.
In the 19 March 2010 Obi record, birds identified by the observers as ceramensis had glossy black upperparts, a clear-cut whitish rump band, and dirty-white belly and undertail-coverts. These were field observations of at least12birds, not a diagnosis for every island population.
For the Sulawesi form sororum, Stresemann’s original description of adults reports black upperparts with a green-blue metallic sheen and a narrow, roughly 7 mm whitish rump band shaded smoky grey, with a dark shaft on each rump feather. The underparts are light silvery grey; the chin feathers are dusky brown.
An extinction-risk assessment has not been added yet.