A sewage treatment plant may not seem like the best place to set up a home, but for a group of displaced birds, it is proving to be the perfect place to start a family.
A group of Tawny Grassbirds have been discovered in the grasslands near Yarra Valley Water’s Lilydale Sewage Treatment Plant, marking one of the first sightings of this species in Victoria.
Tawny Grassbirds are typically found in northern New South Wales and are rarely seen in groups of more than one or two, however, it’s thought that five of these birds have been breeding in the area for the past two months.
Yarra Valley Water’s Biodiversity Officer Chris Farrow said it was too early to know why the birds have migrated so far south.
“With rising temperatures in the northern states, and the shifting weather patterns, we think the birds are basically climate refugees looking for a more suitable home,” he said.
The Tawny Grassbird is roughly 20cm in size, with brown flecked feathers and a long, graduated tail.
“It’s incredible to think that a small enclave of them has gathered, migrated, and are now showing mating behaviours, they’re quite small, so they can’t fly too far.
It’s likely they’re being moving further south each year until they ended up down here,” Mr Farrow said.
Mr Farrow said the Lilydale Sewage Treatment Plant site is perfect for breeding due to the climate, long grass, and proximity to a water source.
“Grasslands have a wonderful cooling effect. If it’s getting too hot in other areas, or if grasslands in their previous habitat are being destroyed, then sites like this become very attractive for species like the Tawny Grassbirds.”
“The birds are insectivores, which mean they primarily eat insects, the site has an abundance of food for them and any new hatchlings.
“We’ll continue to care for them during the breeding and hatching period by protecting the area and minimising human interference.
“Once the mating season ends, we can go in and have a closer look and see what else we can do to help this little colony thrive.
“Ultimately, our goal is to enhance the site for conservation and make sure they don’t need to migrate elsewhere,” Mr Farrow said.
The birds were initially discovered by local birdwatchers and Associate Professor Dr Rohan Clarke from Monash University’s School of Biological Sciences, followed up the sighting to confirm a minimum of five Tawny Grassbirds were present.
“Sewage treatment plants provide important refuges for wetland species, attracting water birds to the treatment ponds and various reed-loving songbirds to the wetland fringes.”
“Lilydale Sewage Treatment plant is an excellent example of this –attracting numerous bird species, it even has a viewing platform for birdwatchers.”
Dr Clarke noted there have been fewer than 10 records of this species from the Greater Melbourne area.
This recent sighting of a group of Tawny Grassbirds is unprecedented in Victoria; most other recorded sightings are of single birds.
“Tawny Grassbirds are a very rare species in Victoria, with just a handful of records to date,” he said.
“The five Tawny Grassbirds found at Lilydale Treatment Plant over summer is the largest group ever observed in the state.”
“It’s possible that these recent Tawny Grassbird sightings around Melbourne are part of a range shift where the species will establish a permanent Victorian population.”
“The Tawny Grassbirds frequented an area of tall grassland adjacent to the treatment ponds because Yarra Valley Water site managers were able to set this aside for the birds, there is an excellent chance the species was able to breed,” Dr Clarke said.
The Tawny Grassbird breeding season will conclude in April/May.
