Monday, August 15, 2016

Incredible trek for penguins

Jamie Morton, the NZ Herald's science reporter

The New Zealand Herald
A rockhopper penguin on Campbell Island. Credit: David Thompson

Call it a happy feat.

New Zealand scientists have been astounded to find that two species of subantarctuic penguin were able to travel 15,000km - equivalent to the distance between Auckland and Boston - over a stretch of just six months.

The insight was revealed by a tagging project observing nearly 100 subantarctic rockhopper and Snares penguins over winter in the Southern Ocean.

"If they are constantly moving this averages out at about 100km a day but you also have to add on to that the distances covered vertically as the birds dive to capture food," said the study's leader, National Institute of Water and Atmosphere seabird ecologist Dr David Thompson.

While the Snares penguin population on their craggy namesake islands was relatively stable, Campbell Island's rockhoppers had dwindled by at least 21 per cent since 1984, leaving just over 33,000 breeding pairs there.

Rockhopper penguins on Campbell Island. Photo: Kyle Morrison
Rockhopper penguins on Campbell Island. Photo: Kyle Morrison
The island was once the world's largest breeding colony of the colourful rockhoppers - the smallest of all penguin species and featured on the movies Happy Feet and Surf's Up - but between 1942 and 1984 the population dropped by about 94 per cent.

Researchers have been trying to understand what has caused the sharp decline, with big changes in their diet a suspected cause.

Thompson said the penguins' led an extreme lifestyle, taking them out into the ocean for long periods of time.

"They come to land to breed and when they finish that, go back out to sea where they feed up for a month," he said.

"Then they come back to land to sit and moult their feathers. During that period they don't eat at all."
Having virtually starved themselves, they then headed back out to sea in poor condition.

"They've grown a whole new set of feathers so their plumage is fantastic but it's quite demanding so they're really scrawny.

"We think winter is pretty important and that there is almost certainly something going on in the ocean causing the population to decline."

The tags attached to the birds had to be modified from fitting the long, skinny leg of an albatross to the short, stubby leg of a penguin.

Thompson and his colleagues also had to time their arrival on Campbell Island, 620km south of Stewart Island, with the end of the moulting season, just as the penguins were ready to leave for the winter.

Then they had to clamber down rock faces and steep cliffs to reach them.

Of the 90 penguins tagged for the project, about 80 returned the following spring when the tags were retrieved and data processing began.

Tracking their movements was an eye-opening exercise.

The Snares penguin headed exclusively west towards Australia, while the rockhoppers went east and covered a wider section of the ocean.

Several birds covered more than 15,000km over the winter.

The tags were also able to determine when the penguins were stationary, indicating they had stopped to dive for food or rest.

Thompson said this first tracking project had provided just a snapshot, but the work had to be start somewhere.

He plans to repeat the project and include other species, such as the erect crested penguin of the Antipodes Islands.

"The extra species will give us more information on how they relate to each other when they go away. It may be that they use different space, or it may be that populations of different islands get together at sea.

"Research like this is important to better understand what's important for penguins. It is possible that particular parts of the ocean may help them get through from one year to the next so we need to be able to identify those places."

"Prior to this study we didn't have a clue where rockhoppers went in the winter but the spaces they use in the ocean might be really important - not only for them but for scientists to better understand what is causing the population decline."


Tuesday, August 2, 2016

Penguin resilience to climate change investigated

August 2, 2016 by Pepita Smyth
Penguin resilience to climate change investigated
Credit: Murdoch University
New research by Murdoch University will investigate the future of Rockingham's beloved Little Penguins colony.
Dr Belinda Cannell, who has been part of a long-term study of the birds, will spend the next three years examining their resilience to that have remained warmer than average since late 2010 .

"Little Penguins are essentially the canaries in the coal mine for the Shoalwater Marine Park," she said.

"Understanding the viability of this population of penguins will give us a good understanding of the health of the whole ecosystem."

Dr Cannell will use new information collected over the next three years, along with data she has previously collected, to improve the understanding of how Little Penguins will fare with climate change and coastal development in the Shoalwater Islands Marine Park.

She will continue to track Little Penguins at sea using satellite and GPS technology, attaching special tags to some birds to record the diving depths when travelling and foraging.

"For the first time we will gain a real understanding of the movements and activities of the penguins in the water and show locations where they may be more at risk from watercraft collisions," she said.
Dr Cannell is also hoping to calculate the size of the penguin population and exactly what the penguins are eating.

"We have not done a full population count of the penguins since 2012 but other indicators have not been promising," she said.

"From 2010 to 2015 far fewer penguins were recorded using nest boxes and, not surprisingly, fewer eggs were laid. We believe this was connected to water temperatures being higher than average.

"The birds have been travelling long distances when they are relieved of incubating the eggs, some travelling down to Geographe Bay. Their foraging trips have been incredibly long, 10 days or more. This indicates food resources close to Penguin Island have been scarce."

Dr Cannell said were still warmer than normal in summer this year, but have now dropped back to normal. She is hoping to see a shift in the ' behaviour, indicating the coastal waters near Penguin Island are again supporting healthy baitfish stocks.

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