Mangrove Honeyeaters are just that. They occur in coastal mangroves and nearby vegetation up the east coast from about South West Rocks in NSW to near Townsville where they are replaced by the very closely related Varied Honeyeater. In fact they are so closely related that some people regard them as a single species. Birds that appear to be intermediate between the two are known from an area between Townsville and Cardwell.

Mangrove Honeyeaters are fairly noisy and can be aggressive. They live in permanent territories in pairs and groups larger than a dozen or so are only seen at rich sources of food such as in coastal gardens where there are many nectar-bearing plants. As well as nectar, they feed on invertebrates including snails and crabs.