Tuesday, May 19, 2015

Study finds Middle Island penguin numbers on the rise

AFTER a slight drop off last season, the population of little penguins on Warrnambool’s Middle Island is again on the rise.

The 2014-15 breeding season has now wrapped up and Warrnambool Coastcare Landcare Group (WCLG) leader Bruce Campbell said while numbers fluctuated from season to season, there had been an upward trend in population growth since 2006, when the group first began monitoring the colony.

The highest number of arrivals this season was 78 on December 23 and the estimated number of penguins on the island is 130.  “There was a shortage of food in the 2013-14 season, so that’s why numbers were low, but they seemed to have bounced back again this year,” he said.  “The breeding season is quite long, the penguins start arriving in July and stay until around April. Adults come ashore and clean out burrows and then when the last chick leaves the nest in late summer, the adults go through moulting and can’t swim,” Mr Campbell said.  He said the increase indicated the Maremma program was continuing to protect the penguins from foxes and other predators.

Mr Campbell said little penguins in Warrnambool generally had two chicks, compared to those on Phillip Island which generally had one.  He said an abundance of food in south-west waters thanks to the Bonney Upwelling pushed food into the area each year.

He said WCLG volunteers monitor the colony in two ways, the first being counts at dusk for two weeks during summer and autumn.  “Dozens of volunteers head over at dusk and count the birds coming ashore after a day out fishing,” he said.  “They then use that number to estimate the total population with a scientific formula.”

He said a smaller number of volunteers go across to the island in the day to count, weigh, measure and microchip chicks in the nests. “That allows us to monitor them year to year and to see where they go.”

Mr Campbell said Deakin University marine biology students were involved in the program, providing them with practical experience.


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