Mangrove swallow

Description:

This swallow averages 13 cm long. The bill is small and black. The adult has iridescent blue-green upperparts, white underparts and rump, and blackish tail and flight feathers. There is a thin white stripe from the bill to above the eye. The female usually has duller colours than the male, and the juvenile is dull grey-brown above and grey-brown washed white below.

Habitat:

Caño Negro, Costa Rica. Seen flying all over the river and its sides. Also accompanying our boat as they had nests on it.