The Australasian bittern (Botaurus poiciloptilus), or matuku as it is known to Māori, is a large, heron-sized bird. They are rarely seen because of their secretive behaviour and excellent camouflage. They are most active at dawn, dusk and through the night.
They live in wetlands throughout New Zealand, although there are fewer than 1,000. When Europeans arrived they were abundant, but now it is rare to see more than one at a time. Australasian bittern are also found in Australia and New Caledonia, but populations there have declined dramatically and they are now classed globally as endangered.
In New Zealand, they are mainly found in wetlands of Northland, Waikato, East Coast of the North Island, and the West Coast of the South Island. The most important site nationally for bittern is Whangamarino Wetland in the Waikato.
Matuku breed deep in wetlands. The distinctive booming calls of male matuku can be heard at the beginning of the breeding season and are often the only sign that they are present in a wetland. The breeding season is long (spread over 10 months) although most eggs are laid in November and December. Birds lays up to 6 eggs.
Matuku feed, mostly at night, on fish, eels, frogs, freshwater crayfish and aquatic insects.
Matuku are important to Māori. They appear in language as part of legends, stories, early pictures and metaphor and there are numerous place names referring to them. They were important for food and their feathers were used for ceremonial decoration.
They are a potential indicator of wetland health because they are dependent on the presence of high quality and ecologically diverse habitats and rich food supplies.
One of the main threats to Australasian bittern is habitat clearance and drainage. Over 90% of freshwater wetlands have been drained and cleared since Europeans settled New Zealand. Wetlands continue to degrade. The major threats to New Zealand's wetlands are grazing, water pollution and taking of water for other uses.
Other threats to Australasian bittern/matuku include:
- Habitat modification and loss of food supplies
- Predation by introduced mammals such as cats, rats, dogs and mustelids
- Human disturbance of nesting bittern
- Road-kills and flying into power lines
Australasian bittern / matuku
Wetlands support a wide range of threatened bird species in New Zealand. However, management techniques for restoring their populations are poorly developed.
DOC is focusing on developing methods for surveying bittern systematically. These methods will enable people to establish baseline data and distribution maps; identify important wetland habitat types for conservation and measure the response of matuku to management such as pest control; and habitat maintenance and restoration.
DOC has been developing ‘call counts’ for bittern. These take place with either an observer listening for set times at dawn or dusk for the booming calls of bittern, or with new automatic recorders (electronic recorders developed by the DOC Electronics Lab) recording calls remotely.
In addition DOC is actively developing methods for restoring wetlands through its Arawai Kākāriki programme. Restoration involves developing a wide range of management tools including methods for controlling introduced predators, methods for managing water levels and restoring wetland vegetation.
You can help
Report all sightings or booming calls of matuku to your nearest DOC office.
Help protect New Zealand's native birds
- Volunteer with DOC or other groups to control predators and restore bird habitats.
- Don’t throw rubbish into water ways or storm drains.
- Set traps for stoats or rats on your property. Get more information from your local DOC office.
- Put a bell on your cat's collar, feed it well, and keep it indoors at night.
- Plant a range of native plants that provide food year-round to encourage birds into your garden.
When visiting parks and beaches
- Only take dogs to areas that allow them, and keep your dog under control.
- Prevent the spread of pests. Check your gear for mice and rats when visiting pest-free islands.
- Use available access ways to get to the beach. Stay out of fenced-off areas. Leave nesting shore birds alone.
- Get your dog trained in avian awareness, and help save forest birds like kiwi and weka.
- Follow the water care code. Keep water craft speed to 5 knots within 200 metres of the shore.