The Australasian Bittern or Matuku Hūrepo is a large wetland bird that is hardly ever seen. This is because they blend into their surroundings, but also because there are fewer of them around than there once were.
Bittern are classified as 'Nationally Critical', the same threat classification as Kākāpō and categorised as in 'serious trouble' by the Parliamentary Commissioner for the Environment 2017.
Just how many are present in the Bay of Plenty is unknown, but a population study by DOC and volunteers is being undertaken from Tauranga through to Whakatāne to try and find out.
Whakatāne biodiversity ranger Cameron Houston said it is now rare to see more than one bittern at a time after their numbers declined greatly following the destruction of 90% of their wetland habitat to create farmland and towns.
In the Bay of Plenty region alone, just 2-3% of the original 41,000 hectares of freshwater wetlands remain.
"We want to understand more about population trends in the area and the implications of wetland management practices on bittern populations."
And volunteers are needed to help.
"If you would like to volunteer to support this survey, DOC Whakatāne has a listening survey planned for October 29th to 31st in Matata Wildlife Refuge Reserve for an hour each night," Mr Houston says.
From late October during the bittern breeding season adult males call with a distinctive 'vooom' at twilight. That's what volunteers will be listening for.
"Minimal experience is required – just your ears."
