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).