Both sexes have a blue-grey back, a white collar and a single blue-grey breast band. The female adds a second, chestnut band across the belly with rufous extending down the flanks. A bird can therefore be sexed at a glance, which is unusual and useful for field study.
Why the female is brighter is unresolved. Belted kingfishers do not have reversed sex roles: both sexes dig the burrow, incubate and feed young. Proposed explanations include signalling quality to males, individual recognition at the nest, or a trait retained from an ancestor rather than currently maintained by selection.
The nest itself is a tunnel of roughly one to two metres bored horizontally into a bank, ending in an unlined chamber. Pairs excavate together using bill and feet. Fish bones and scales accumulate as pellets in the chamber, and the species will also take crayfish, amphibians and insects when fish are scarce.