In 2015 Friends of Mangarakau, with the help of Colin O'Donnell and Emma Williams from DOC, set up recording devices to monitor the booms of male Australasian Bitterns. The sound recorders recorded for 2 hours morning and evening for 3 weeks in the peak bittern booming season. Comments on 2015 recordings.
The work was repeated on a larger scale in 2016, with additional help from six teams of two volunteers manually recording the bittern booms at dawn and dusk for five days.
From these observations the booming signatures could be read and counted and statistical analysis was used to calculate how many birds are likely to inhabit the swamp .
We are now confident there were at least eight and possibly as many as twelve male birds present at Mangarakau during the breeding season.
For more details on this elusive bird, including links to some sound files of bittern booming, check these websites:
A painting from about 1844 of the Australian Bittern by English artist and ornithologist John Gould
The many hours of sound recordings were listened to and analysed using software which produced an image of the sounds recorded.