Increasing occurrence of House Swifts Apus nipalensis in Australia and an influx event to Darwin, Northern Territory

The House Swift Apus nipalensis has an increasing range across Asia and is a vagrant to Australia. Within the Northern Territory, it was previously known from a single 1979 record which is also the first Australian record. An influx of birds to Darwin, Northern Territory, occurred in early 2019, with numerous sightings of up to 7 individuals between January and May. Most birds were in the company of Pacific Swifts A. pacificus, from which the House Swift can be distinguished by its noticeably smaller size, shorter and blunter wings, shorter body with a short, shallow-forked tail, and a lack of defined white scalloping on the underparts. Combining cases accepted by the Birdlife Australian Rarities Committee with records from the citizen science database eBird, there are now close to 40 confirmed records of the species in Australia, the bulk of which are from northern Australia, and records of House Swifts in Australia are increasing. The species has undergone a recent and likely ongoing range expansion, including to Indonesian islands close to northern Australia. This may eventually result in colonisation and establishment of breeding in Australia.