Bittern will soon be booming out their fog-horn like calls from Northland wetlands, saltmarshes and the odd flooded paddock – meaning it’s time to get stuck into trying to detect them again.
Australasian bittern, or matuku hūrepo, are large, secretive wetland birds on the brink of extinction – they are more often heard than seen. Matuku populations have been decimated by wetland drainage and habitat clearance. Introduced pests such as rats, stoats and feral cats predate adults and chicks, even eating their eggs on the nest. It is estimated that only 900 mature individuals remain nationwide – but how many do we have left in Northland?
Currently, there is only a limited understanding of Northland’s matuku hūrepo distribution and no regional population trends have been established to identify if the region’s bittern population is declining, stable or increasing.
In 2023, the first stage of a collaborative “Matuku Mahi” or Australasian bittern monitoring project was carried out across Northland. Kiwi Coast worked together with the QEII National Trust Northland Fish & Game, Northland Regional Council, Department of Conservation, Royal Forest & Bird Society, Love Bittern and the Shorebird Trust, farmers, community groups and bittern enthusiasts. The collaborative aim was to investigate bittern distribution (presence) via deploying acoustic recording devices (ARDs) during the peak of male bittern ‘booming’ in spring when they are most likely to be detected.
The 2023 survey was a great success. Bittern were successfully detected at 44 of the 78 sites surveyed, with five sites recording over 1,000 bittern booms (Read or download the 2023 Survey Report here). It’s now time to carry out Year 2 of the survey.
Luckily while they may be difficult to see, they are easy to hear. During the bittern breeding season in spring males produce a “boom” sound to attract females and to guard their territory from other males. Just as we do for kiwi, we can listen out for bittern and compile results to get a regional snap-shot of where things are at.
If you are not sure what a bittern boom sounds like listen to bittern booming here (credit Nicholas Allen) (WAV 1.98 MB)
Kiwi Coast is one again keen to work with Northlanders keen to help bring bittern back from the brink. There are three things you can do:
- Report bittern sightings, calls and known regular bittern locations either via the NRC dedicated Bittern Encounter Form or iNaturalist
- Let us know if you would like help to survey for bittern in your local wetlands. We will help you put out an Acoustic Recording Device to try and detect their calls – contact Ngaire Sullivan, Kiwi Coast Coordinator.
- Find out more about bittern – come along to the Hokianga Matuku Workshop being run with Love Bittern Trust in October.
