Tree martin (Hirundo nigricans)

Also known as: Australian tree martin
Synonyms: Petrochelidon nigricans
GenusHirundo (1)
SizeLength: 13 cm (2) (3)
Weight14 - 19 g (2) (3)
Top facts

The tree martin is classified as Least Concern (LC) on the IUCN Red List (1).

The tree martin (Hirundo nigricans) is a small member of the Hirundinidae family, a group which includes the swallows and martins (3) (4). It is recognised by its glossy blue-black crown and back, whitish underparts, dull white rump and reddish-brown forehead, as well as by its short, slightly forked tail (2) (3) (4). The tree martin also has fine black streaks on its throat and breast (2) (3) (4), and its wings and tail are blackish-brown (2) (3).

The area between the tree martin’s beak and eyes is black, and the sides of the head are brownish. There is also a pale reddish-brown tinge on the flanks (2) (3). The male and female tree martin are similar in appearance, while juveniles are duller and browner than the adults, with a paler forehead and underparts and pale or reddish-brown edges to the feathers (2) (3) (4). The tree martin has a black beak, dark brown eyes and blackish-brown legs and feet (3).

Three subspecies of tree martin are generally recognised, with Hirundo nigricans nigricans being larger than Hirundo nigricans neglecta, and Hirundo nigricans timoriensis having heavier dark streaking on the throat (2) (3). The tree martin’s whitish rump and shallowly forked tail help distinguish it from other Australian swallow species (3) (4), and it differs from the most similar species, the fairy martin (Hirundo ariel), by its blue rather than reddish-brown head and nape (2) (3).

The tree martin’s song is a high-pitched twittering, and it uses a ‘tsweet’ note as a contact call (2) (3) (4).

The tree martin is widespread across Australia, including Tasmania, and also occurs further north in New Guinea and the Lesser Sunda Islands. Vagrants are also occasionally recorded in New Zealand and New Caledonia (2) (3) (5). The subspecies H. n. nigricans is found in Tasmania and eastern parts of Australia, while H. n. neglecta is found in western and northern Australia and H. n. timoriensis occurs only on Timor and possibly also Flores, in the Lesser Sundas (2) (3).

Although many tree martins remain in the same areas year-round, some southern populations migrate northwards at the end of the breeding season, spending the winter in northern Australia, New Guinea and on surrounding islands (2) (3).

The tree martin is typically found in open woodland habitats, often near water (2) (3) (4). It is also commonly seen in urban areas, even breeding in large towns and cities (2) (3).

The tree martin usually forages alone or in small flocks, flying quite high above the ground as it pursues its prey in the air with a rapid, agile flight (2) (3) (6). The diet of this species comprises a variety of insects, and it also takes some spiders. Feeding usually takes place over and around trees, over water bodies or farmland, and even occasionally over the sea (2) (3).

The breeding season of the tree martin generally runs from July or August to January, although in dry areas this species may breed opportunistically after rains. Breeding usually takes place in solitary pairs or in small groups of around two to ten pairs, and the nests may be built in a tree hole, a crevice in a cliff or cave, or sometimes on an artificial site such as a bridge, pier or building (2) (3).

The tree martin’s nest is a relatively flimsy structure made from dry grass, leaves and sometimes feathers (2) (3), although it will occasionally use some mud or even build a full mud nest (3). If a crevice is used, the tree martin may reduce the size of the entrance using mud pellets mixed with plant fibres. It has also been known to take over the nests of welcome swallows (Hirundo neoxena), building up the walls with mud and lining the nest with leaves. Tree martins may reuse the same nests over a number of years (2) (3).

The eggs of the tree martin are white with light brown and purplish spots (3), and three to five are usually laid per clutch. Little is known about the incubation period of this species, or about the time it takes tree martin chicks to leave the nest. However, breeding pairs are known to often produce two broods of young each season (2) (3).

After the breeding season, the tree martin is often seen in large flocks, with hundreds or even thousands of individuals sometimes roosting together in reeds or eucalyptus trees (2) (3) (4).

The tree martin is a common and widespread species, and is not currently considered to be under threat (2) (5). Although it mainly uses natural nest sites, this species is increasingly using artificial sites, and this new habit may help its population to expand (2) (3).

The tree martin is listed as a protected species under the Environment Protection and Biodiversity Conservation Act 1999, which provides a legal framework for the protection and management of Australia’s wildlife and environment (7). No other specific conservation measures are known to be in place for this small bird at present.

Find out more about the tree martin and its conservation:

More information on conservation in Australia:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (March, 2013)
  2. del Hoyo, J., Elliott, A. and Christie, D. (2004) Handbook of the Birds of the World. Volume 9: Cotingas to Pipits and Wagtails. Lynx Edicions, Barcelona.
  3. Turner, A. and Rose, C. (1989) A Handbook to the Swallows and Martins of the World. A&C Black, London.
  4. Dutson, G. (2011) Birds of Melanesia: Bismarcks, Solomons, Vanuatu and New Caledonia. Christopher Helm, London.
  5. BirdLife International - Tree martin (March, 2013)
  6. Tzaros, C. (2005) Wildlife of the Box-Ironbark Country. CSIRO Publishing, Collingwood, Australia.
  7. Department of Sustainability, Environment, Water, Population and Communities (2013) Petrochelidon nigricans. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at: