The number of little penguins on Kangaroo Island has plummeted by more than 70 per cent since 2011, with three previously active colonies now believed to be extinct, according to the first all-island survey to be carried out in more than a decade.

Officers from the Kangaroo Island Landscape Board (KILB) carried out the survey in November 2023 and recently released the results.

There are now thought to be 558 breeding adult little penguins across the 12 surveyed colonies on the island.

Efforts at Emu Bay to improve habitat may have helped that colony buck the trend with a small rise in numbers since 2013.(Supplied: Kangaroo Island Landscape Board)

This compares to 1,348 in 2011, however the biggest decline in numbers occurred between 2011 and 2013, when only 566 birds were counted, the last time an island-wide survey was conducted.

The latest survey shows the decline has continued but researchers say there are positive signs for the colony at Emu Bay, which increased its population by 20 birds over the past decade.

The colony at Kingscote, the site of the island’s biggest town, was once the largest but has now lost more than 90 per cent of its population, now totalling only 74 birds.

Colonies at Cape Cassini, Brown Beach and Western River Cove are believed to now potentially be extinct.

Project officer Alex Comino said the 2023 total island population estimate was conservative and that there may be pockets on the island with one or two penguins that weren’t counted.

She said “time will tell” whether the colony at Kingscote would also become extinct.

Ms Comino said there had been data in recent years from individual colonies and anecdotal reports from farmers and residents for some time about the decline in numbers.

“People have told us, ‘there used to be penguins here and I could hear them a lot and I just have not heard them in the last few years,” she said.

She said the island-wide survey now provided the “bigger picture” and would be repeated annually.

Alex Comino led the the first island-wide survey undertaken in more than a decade.(Supplied: Kangaroo Island Landscape Board)

Ms Comino said the efforts of groups such as the Kangaroo Island Wildlife Network to re-establish habitat at Emu Bay have helped that colony, along with the board’s program to rid the island of feral cats.

“It’s been a communal effort and driven by the passion in the community,” she said.

Weeds and, in particular, kikuyu grass, which pushes out native vegetation and forms mats that penguins find difficult to get through, are also a problem.

Surveying by stink

Ms Comino said staff surveyed the penguins by looking for active burrows rather than the birds themselves.

Little penguins tend to forage all day and return to the burrow in the evening.

“Their schedules are all over the place,” she said.

She said they were often noisy as they tried to find each other, and squabbled over burrows.

But the biggest sign of an active burrow was the smell.

“It’s very, very smelly — smells very fishy and acrid and it’s a very specific kind of pooey smell.”

Once calculated, the number of active burrows found is doubled to arrive at the estimated number of adult breeding penguins per colony.

One of the natural burrows at the Vivonne Bay colony which had 54 little penguins in 2023, compared to 126 in 2011.(Supplied: Kangaroo Island Landscape Board)

Little penguin researcher Dr Diane Colombelli-Negrel, from Flinders University, said she also was not surprised by the survey numbers, having carried out colony specific surveys in recent years.

She said the decline was due to a combination of factors including terrestrial predation, predators at sea, climate change aspects, food availability and also disease.

Feral cats are the apex predator on the island.(Supplied: Kangaroo Island Landscape Board)

She said it was important to continue to improve the habitat for the penguins and to continue the cat eradication program on the island.

“Yes, the numbers are down but at the same time I have to think, they’re still there as well, so there’s still hope.”

Dr Colombelli-Negrel said it was difficult to say whether the extinct colonies could revive but it was not impossible with the little penguins having a “high fidelity” to the areas they were born in.

Cat-free island

The KILB is working with a number of agencies and farmers to rid the island of all feral cats by 2030, in conjunction with a phasing out of all domestic cats. Currently all domestic cats on the island must be contained to a house or contained run, and be desexed.

An eradication program has removed more than 3,000 feral cats from Kangaroo Island.(Supplied: Kangaroo Island Landscape Board)

Chantelle Geissler, from the feral cat eradication team, said that more than 1,000 cats had been removed from the island’s Dudley Peninsula, which has three little penguin colonies including the one at Penneshaw. 

Another 2,000 cats have been removed from the western side of the island as part of efforts to help native wildlife recover from the 2019/2020 bushfires.

“They [cats] are pretty unique that they’re the apex predator on the island, the island being free from wild dogs and feral foxes as well.”

Chantelle Geissler of the Kangaroo Island Feral Cat Eradication Team.(Supplied: Kangaroo Island Landscape Board)

All cats caught in the KILB cages are scanned for microchips, with any roaming pet cats returned to their owners by the local council, along with a hefty fine.

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