30-07-2025
Weeding project on WA island helps little penguin population
Standing around 30 centimetres high, the average little penguin can struggle to shake off larger predators and opponents.
But the presence of 1.5-metre-high weeds at a key breeding site off Western Australia's southern coast has required human intervention.
The island, which the ABC has chosen not to identify at the request of researchers, hosts a large number of little penguin nesting burrows.
But an infestation of the invasive perennial weed Chasmanthe floribunda, also known as African corn-flag, has been stopping the penguins from moving freely around the island.
Belinda Cannell from the University of Western Australia's Ocean Institute said weeds could have a devastating impact.
"Weeds have been shown to demolish colonies of little penguins elsewhere in Australia," Dr Cannell said.
The weeds tower over the small birds, also known as fairy penguins.
Little penguins tend to return to the same landing areas on the island and then walk up to their burrows, making access critical, so a group of researchers and volunteers teamed up to spray, weed, and open paths on the island.
"That's why we're opening up areas. Because while some of the burrows can be near the rocks on the island, others can be further up from where they land," master's student Isha Barve said.
Ms Barve's master's project focused on weed management and the impact on little penguins, looking at part of the island, and building on previous research.
"Chasmanthe floribunda sprouts in June/July and can keep growing until November, so it's smack in the middle of their breeding season, which is a big problem."
UWA researcher Harriet Paterson said previous vegetation surveys showed the weeds covered about 80 per cent of the island.
DBCA (Department of Biodiversity, Conservation and Attractions) sprayed some paths suggested by the team, and volunteers and TAFE students assisted in hand-weeding more difficult-to-get-to areas.
"Obviously, where they've been sprayed, they've gone away," Ms Paterson said.
Ms Barve said her research showed penguins had been using the paths created.
Previous population estimates suggested there were 123 breeding pairs of little penguins on the island.
"I came along two to three years later and I have found at least another 31 burrows on the island that weren't marked previously, which is a really good thing," Ms Barve said.
Dr Cannell said little penguins inhabited several other islands on the south coast.
"The south west is really important because terrestrial temperatures hopefully will not get into what we call the thermo-neutral zone," she said.
"For the little penguins, that's when they start to become stressed and if it continues to climb then they become overheated and they actually die from hyperthermia.
"It could happen, but hopefully it's less likely to happen in Albany. It certainly happens in Perth."
Pollution was another threat the species faced.
"Marine pollution certainly is a potential issue and I've had two students now who've found microplastics in the faeces of the penguins," Dr Cannell said.
"We don't know what impact these very small pieces of plastic are going to have on the body condition, or maybe even longer term with respect to things like other illnesses the birds might get."
