Australasian bitterns, or matuku, are endangered native birds that live in wetlands.
The brown, heron-sized birds are shy - their spotty brown plumage providing excellent camouflage as they stand stock still with their bills pointed skyward. They feed mainly at night, on fish, eels, frogs, freshwater crayfish and aquatic insects.
"Regularly seeing bitterns on my farm gave me the idea of establishing a bittern sanctuary because a successful dairy farm and native wildlife can go hand-in-hand," Mr Lupton said.
He is achieving his goal with help from Living Water, a partnership between Fonterra and the Department of Conservation which works with dairy farmers, iwi, conservation groups, schools and other agencies in five key catchments in significant dairying regions, including the Hikurangi catchment that feeds into the Kaipara Harbour.
The focus is on increasing ecosystem resilience and farm profitability, including improving water quality and increasing native wildlife.
"The first step in building the sanctuary, is finding out how many bitterns are living on the farm," said DoC Ranger Olly Knox, who co-ordinates the work. "Male bitterns make a booming sound, with each male making its own distinctive sequence of booms.
"Living Water funding will be used to buy digital recorders to record the bitterns booming on Ian's farm."
The funding will enable Mr Lupton to control stoats and feral cats which eat bittern eggs and chicks, and to control weeds. Living Water also funds native plantings along the farm's canal and drains.
This improves water quality by reducing sediment and nutrient runoff. And it provides habitat for fish, eels, frogs and aquatic insects, increasing the bittern's food.
Dargaville High School is supplying native plants for the project. Enviroschools Northland facilitator Jacque Knight worked with teacher Tim Pratt to establish the nursery with students.
"The students are making monthly visits to the farm to record sightings of bitterns, noting details of the vegetation and conditions they favour. These are secretive birds. If we can learn more about the habitat and conditions they like, we can recreate these as we build the sanctuary," she said.