Census reveals Granite Island penguin numbers on the up

Encouraging results suggest penguins are making a comeback on Granite Island, according to the latest census.

A count of Little Penguins living on the island confirmed numbers have increased from 16 to 28 adults since October 2016.

For the census, volunteers joined staff from Natural Resources Adelaide and Mount Lofty Ranges and Flinders University, spending four hours gently checking burrows for adult birds, chicks and eggs.

Senior Ranger Seiji Iwao was excited to see it confirmed that penguins continue to live and breed on Granite Island.

“Granite Island now has the highest breeding success rate in South Australia. Last year’s breeding season was the best recorded for some time: let’s hope the fledging rate is just as high this year,” Mr Iwao said.

Mr Iwao thanked the Friends of Granite Island, who also undertake regular weed control and revegetation works around the burrows with specially chosen plants suitable for nesting material.

Census co-ordinator Dr Diane Colombelli-Négrel from Flinders University said she was happy to see so many enthusiastic participants at this year’s census.

“The involvement of volunteers on census day is critical to making sure that we cover the whole island in a short amount of time – leading to more accurate results.

“Seeing a stable population over the past two years has given us a real reason to be hopeful for the future of Granite Island’s penguins.

“Breeding season extends until February and we are very optimistic that this year will be as successful as the last,” she said.

On November 7, at Carrickalinga House, more than 30 people attended an information evening on the Little Penguins on Granite Island.

Granite Island tour guide Stephen Hedges was the key speaker on the night and has spent 40 years studying the environment and 20 years studying penguins in particular.

Mr Hedges confirmed the numbers of Little Penguins on Granite Island were on the rise.

The Inman River Catchment Landcare Group organised the evening and chair Di Sinclair-Warren said it was an informative night.

“The life span of a penguin averages to be five years and can be as long as seven and they can miss out on a breeding season due to weather patterns, which impacts on numbers,” Ms Sinclair-Warren said.

“The penguins travel 150 kilometres in a day searching for food and Steve said a drop in numbers has occurred and one reason was due to a rat infestation and DEWNR reacted and undertook a baiting program.

“Oceanic Victor is supportive of the Granite Island penguin colony and Steve believes penguin numbers should continue to rise.”  

A new study led by Flinders University has found that disparities in habitat, rather than geographic isolation or other factors, seem to be the key driver of variation in the sounds Little Penguins use to communicate.

The study by Dr Colombelli-Négrel and Rachel Smale, UNSW, examines differences in the calls of Little Penguins from four colonies in Australia.Developing a greater understanding of the differences in calls could help conservation efforts for Little Penguins.

“Birds use vocalisations to attract mates, defend territories, and recognise fellow members of their species, but while we know a lot about how variations in vocalisations play out between populations of songbirds, it has been far less clear how this variation affects birds such as penguins in which calls are inherited,” Dr Colombelli-Negrel said.

Their paper, Habitat explained microgeographic variation in Little Penguin agonistic calls, is published in leading journal The Auk: Ornithological Advances.