Despite being distributed from New Zealand and Australia to New Caledonia, the Australasian bittern is globally endangered. It is thought to number fewer than 1,000 individuals in New Zealand. Bitterns inhabit swamps and wetlands throughout the country and are famously cryptic. They are masters of camouflage, and when spotted they will adopt a ‘freeze’ position with their bills pointed skywards. Bitterns move large distances to make the most of their fragmented wetland habitats. The distinctive booming calls of male bitterns can be heard from July onwards, ahead of their August to December breeding season.

These birds are prone to numerous threats, including predation from introduced mammals, poor water quality, and reduced food availability. The decline of the Australasian bittern has mirrored the destruction of New Zealand’s wetlands – only 10% of which remain.

(Information adapted from New Zealand Birds Online)