Main Club 3 May 2024
Dr Erin Clitheroe is a Postdoctoral Research Fellow at Murdoch University, an avid birder, and a conservation biologist deeply committed to protecting seabirds in the face of climate change. Her special interest is the Little Penguin, Eudyptula minor.
Erin began her talk with a wonderful story about how, at Christmas 2021, she saved dozens of Little Penguins on Penguin Island with the aid of 50 frozen water bottles! For four consecutive 40-degree days, the penguins snuggled up to the cold-water bottles that Erin had put into their burrows. Although many in the colony died of heat stress, all those that were given the water bottles survived.
This was not a normal year. Record high rainfall in July delayed their breeding season, meaning the chicks were still in nests in December and exposed to record heat. However, warming weather since the 2011 marine heatwave has meant that the Penguin Island colony has declined by 80%.
There have been some good years, but overall, fewer penguins are breeding, but breeding success is showing a declining trend. Fingers crossed; it stays that way. Overall, boat strikes are the biggest killers in the water.
The Penguin Island population is the most northerly and isolated colony in WA, the next being at Augusta. They are genetically different and diverse, with a different breeding strategy. It is a “canary in the coalmine” for Climate Change, with temperature being its limiting factor, especially sea-surface temperature. It is also a top-rated tourist attraction with high social and economic value.
Little Penguins lay their eggs between April and October, with chicks sometimes still in nests in October. The peak breeding time is June to September, and moulting is in summer. But on land, they become heat-stressed at 30C, die at 35C, and are most vulnerable when moulting. At Penguin Island, they rely on vegetation for nesting because they can’t burrow in the sandy soil. But drought-stressed vegetation is not very cooling. Artificial boxes were installed 35 years ago. The penguins liked the boxes, but they are often too hot, becoming an ecological trap!
Other dangers include rat plagues and boat hits. Also, moulting penguins can’t reach the shore to cool off when people are on the beach. Little Penguins are faithful to their breeding island and only look for nesting sites at the location where they come ashore. These habits rule out the possibility of a better habitat.
Erin talked about ways of providing cooler nesting sites, such as nesting boxes that are white painted, shaded, insulated, or ventilated. Misting under the boardwalk has been a great success for moulting penguins. Another is to copy the vegetation of the coolest sites on the island. Heat maps were used to determine this, and it was found to be where the drought-tolerant Nitre Bush Nitraria billardierei was growing. However, a successful way to propagate it has not been found.
Erin says that the Penguin Island population will probably only recover with help and that we must work quickly and cooperatively to find new solutions.
Mike Gregson