Nesting of the Grey-rumped Treeswift

Grey-rumped Treeswift (Hemiprocne longipennis) is a common resident in Singapore. At rest, it is easily recognised by the long wing tips crossing over the shorter forked tail (above). The male has rufous ear-coverts (above) while the female’s ear-coverts are blackish (below).

The nest is a half-saucer of hardened saliva that incorporates pieces of moss, bark flakes and body feathers, possibly from the treeswifts themselves. It is attached to the side of the slender tree branch.

Because the nest is frail and delicate, the adult treeswift does not sit directly on the nest to incubate the egg (above). Rather, it rests on the branch with its tarsus (foot) over the nest and the talons clutching the edge of the nest. In this way the brood patch is in contact with the egg (below).

Both adults help build the nest that measures 36 x 24 mm and 12 mm deep from the outside. A single white egg is laid, measuring 25.6 x 17.4 mm (Wells, 1999) and is stuck to the surface of the nest with the help of the bird’s saliva (Chantler, 2000) (below). Both adults share in the incubation of the egg that takes at least 50 days to hatch. Similarly, both adults help in brooding the chick.

Johnny Wee
Singapore
February 2014

References:
1. Chantler, P. (2000). Swifts. A guide to the swifts and treeswifts of the world. New Haven & London: Yale University Press. (2nd ed.)
2. Wells, D. R., 1999. Family Hemiprocnidae (Tree-swifts). In del Hoyo, J., A. Elliott & J. Sargatal (eds.), Handbook of the birds of the world. Vol. 5. Barn-owls to hummingbirds. Lynx Editions, Barcelona. Pp. 458-466.