The Collared Kingfisher is a medium-sized kingfisher belonging to the family Halcyonidae, the tree kingfishers. It is also known as the White-collared Kingfisher or Mangrove Kingfisher. The Collared Kingfisher is 22 to 29 cm long and weighs 51 to 90 grams. It varies from blue to green above while the underparts can be white or buff. There is a white collar around the neck, giving the birds its name. Some races have a white or buff stripe over the eye while others have a white spot between the eye and bill. There may be a black stripe through the eye. The large bill is black with a pale yellow base to the lower mandible. Females tend to be greener than the males. Immature birds are duller than the adults with dark scaly markings on the neck and breast. It is most commonly found in coastal areas, particularly in mangrove swamps. It also inhabits farmland, open woodland, grassland and gardens. In some parts of its range, especially on islands, it can be seen further inland, ranging into forest or into mountain areas, wires, and rocks or bare branches. Birds often perch conspicuously on Small crabs are the favoured food in coastal regions but a wide variety of other animals are eaten including insects, worms, snails, shrimps, frogs, lizards and small fish. The bird perches almost motionless for long periods waiting for prey. When it spots something it dives down to catch it and then flies back to the perch where larger items are smashed against the branch to subdue them. Any indigestible remains are regurgitated as pellets.