19 March 2012

Boasting little penguins build their reputations

NEW ZEALAND - Take that, loser! By showing off after they win a fight, male little penguins make it less likely that other males will challenge them, a study by University of Waikato scientists has found.

The study, published in Animal Behaviour, used an innovative method to look at the effect of 'triumph displays' on nearby little penguins - 'social eavesdroppers' - at Flea Bay in New Zealand.

The researchers edited audio recordings of fights among two sets of little penguins (who don't live at the colony) into two 'fights', each ending with a triumph call. First, they played the recordings to penguins nesting in their burrows through speakers set up 5 metres away. Then, 5 minutes after the 'fight' was over, they played either the winner's triumph call or a call from the loser from speakers set up 2.5 metres away from a burrow - making the burrow's inhabitants think the winner or the loser was coming closer.

Cleverly, the nesting penguins' stress levels were measured by using an infrared egg, temporarily switched for their real egg, that monitored the penguins' heart rate.

Both male and female penguins were stressed (had increased heart rates) while listening to the fights, with females similarly stressed regardless of whether a winner or loser approached their burrows. Males, however, were more stressed if a winner, rather than a loser, approached their burrows, and were also less likely to challenge an approaching winner by calling. Females stayed silent no matter whether the winner or loser approached.

The findings suggest that by advertising their victories, i.e. boasting, male penguins may establish a ‘reputation’ for winning fights within the colony, potentially reducing the likelihood of being challenged in the future.

Animal Behaviour citation
Triumph displays inform eavesdropping little blue penguins of new dominance asymmetries, Solveig C. Mouterdea, David M. Duganzichb, Laura E. Mollesc, Shireen Helpsd, Francis Helpsd, Joseph R. Waas, Animal Behaviour, Volume 83, Issue 3, March 2012, pp.605–611

Sources
How to say 'in your face' like a penguin by Jane J. Lee, 9 March 2012, ScienceNOW
Why little penguins 'show off' (photo gallery), 8 March 2012, BBC Nature News

12 March 2012

No. 337: Penguin at large

JAPAN - A Humboldt penguin known only at No. 337 is still on the loose after escaping from Tokyo Sea Life Park at least five days ago.

Keepers were not even aware the one-year-old penguin was missing until they received a photo of it swimming in Tokyo Bay last weekend.

No. 337 had to scale a rock wall and a squeeze through a fence to break out of the penguin enclosure. The height of the rock wall varies between 1.2m and 4m - quite a big leap for Humboldt penguins, which grow to 56-70cm long.

Park staff have speculated that something may have startled the bird, leading it to climb over the wall.

The park has asked Tokyo residents, birdwatchers in particular, for help in finding the bird, and are regularly patrolling the shoreline with binoculars. Humboldts generally stay close to shore, although I don't know if this will apply to No. 337, as this penguin has already proven itself to be quite the adventurer.

Satoshi Toda of the Sea Life Park told AFP that park staff are hopeful the fugitive is still alive after receiving information that it had caught and eaten some fish.

Sources
Fugitive penguin no. 337 flips Tokyo park the bird by Ruairidh Villar, 7 March 2012, Reuters
Japan widens hunt for escaped penguin, Sapa-AFP, 9 March 2012, Times Live

07 March 2012

Grim reaper cuts swathes through the little penguins of Perth

Gbrqs7c6-1330659517
For whom the bell tolls: a little penguin.  
Photo credit: Belinda Cannell
By Belinda Cannell, Research Associate at Murdoch University

This article was originally published at The Conversation. Read the original article

AUSTRALIA – Little penguins off the coast of Perth are being found dead – starved, battered, and in some cases almost completely beheaded – as elements both natural and manmade conspire against them.

Penguin Island, 50 km south of Perth and just 600 m offshore from a rapidly growing urban area, is home for a very special colony of little penguins, which are the smallest of the penguins with an average height of 33 cm. Penguin Island is not only the largest colony in Western Australia, but it also has the highest conservation status of all major colonies in Australia. In addition, there are no little penguin colonies further west in the world.

In the Perth region, a smaller colony is also found on Garden Island, just seven kilometres north. It lies at the western edge of Cockburn Sound, the busiest bay in Western Australia. The two colonies together are regarded as one “metapopulation”.

This metapopulation of little penguins is the most northern in WA. It is facing an increasing range of natural, anthropogenic and climate-change threats.

From August-December 2011, the number of penguins found dead increased four-fold. Forty-nine penguin corpses were found on the foreshore between Safety Bay and the mouth of the Donnelly River, some 400 km around the coast from Penguin Island, as well as on Penguin Island. The penguins were mostly banded or microchipped, so I know that most of them came from Penguin Island.

With the support of the Department of Environment and Conservation, autopsies were performed on many of the penguins, and the major cause of death was starvation. This is most likely to be linked to high sea surface temperatures and other oceanographic changes associated with a strong La Nina and a very strong Leeuwin Current (a warm current that flows south along the WA coast).

This “marine heat wave”, as it has been labelled by the Department of Fisheries, is suspected of causing a decline in stocks of fish that the little penguins rely on for food. Indeed, sandy sprat, usually their major prey item while raising chicks, were not found in the penguins’ diet in 2011. The species of fish the penguins were feeding on was determined by analysing the DNA in their faeces.

The penguins also had the worst breeding season since monitoring of this colony began in 1986, with many fewer penguins even attempting to breed. The penguins must remain close to the colony while raising chicks, so they can return each night or two to feed them, so it is likely that the nearby fish resources were much less abundant than normal.

If this wasn’t bad enough, the lack of fish has most likely contributed to more penguins being found dead during their annual two-week moult. Penguins cannot go to sea and catch fish while they are moulting, so they must build up enough fat and protein before moulting to “feed” this very energetically demanding process of making new feathers. If the fish are less abundant, and the penguins have to travel further to catch them, then they can’t build up enough reserves to last the fasting stage of moult.
It tolls for thee: little penguin found with a
broken wing and dead.
Photo credit: Belinda Cannell

Sadly, we have also found quite a few penguins with injuries from watercraft. These injuries include deep cuts across their backs or feet, bleeding under the skin with no external wounds, broken necks and even completely severed necks.

A boat ramp has recently been constructed seven kilometres south of the colony. We don’t yet know if a potential increase in watercraft used in the area has caused this increase in deaths from injuries. The penguins could be weaker due to starvation and unable to get out of the way of the watercraft, or it could be a combination of both. We need to know more about the seasonality of dead penguins, where they are found and their causes of death, to know what effect the boat ramp is having.
Perth has just experienced its hottest summer on record. This also contributed to a number of deaths, particularly in moulting penguins. They are unable to leave the island until their new feathers have become waterproof, so some penguins died from overheating.

It was probably lucky that there were very few chicks that hatched this year. Otherwise they could have died from overheating too, as I have witnessed in past years. The predictions for the changes associated with climate change – warming temperatures and less rain in the south-west of Australia – do not bode well for this colony of penguins.

It’s hard to know how the mortality and low breeding observed in 2011 will affect the overall survival of the colony. Certainly, a population estimate I undertook in 2011 showed that there were fewer adults on the island compared to the estimate of 2369 penguins in 2007. However, this is likely to be an indication that there were fewer penguins breeding, as was certainly identified from the monitoring of nest sites.
Seabirds are long lived, the adults usually have a high survival rate, and young penguins don’t join the breeding population until they are two to three years old. Therefore, marked changes in the population are likely to occur over the macro-scale.

However, it is likely that the survival rate of the adults in 2011 was much lower than normal. Also, very few chicks were raised, and those that did leave the nest would have a slim chance of surviving if fish weren’t available close by.

It is likely that we will see a real decline in the population over a shorter time scale, especially if La Nina conditions continue.

But all is not lost for the Perth penguins; not yet, anyway. The colony on Garden Island did not appear to fare so badly. Their breeding participation and success was much better than that at Penguin Island – it usually is. This is probably because they feed in Cockburn Sound: just a short trip out the back door for these penguins. And for whatever reasons still to be identified, the fish stocks the penguins feed on in Cockburn Sound were apparently not affected by these high sea temperatures.

These penguins also nest in lovely cool limestone, unlike the penguins on Penguin Island who nest under bushes or in nesting boxes. So they are unlikely to be affected to the same extent by high air temperatures.

So this colony of penguins might be the saviour for penguin presence in Perth if we are unable to manage all the threats the penguins on Penguin Island are exposed to. We just need to maintain all the things that are responsible for them doing so well. We just don’t know what all of those are yet!

Watch a video about the little penguins.

05 March 2012

Study predicts climate change will shift penguins' food sources

King penguins in the Crozet Islands.
Photo by ¡WOUW!. Some rights reserved.
SUBANTARCTIC - King penguins' main food sources will move south as climate change warms the sea surface, a new study published in Proceedings of the Royal Society B shows.

Scientists from CNRS in France used a long-term tracking dataset of king penguins breeding on the subantarctic Crozet Islands to understand and model where adult penguins forage while they are incubating and brooding chicks, and to predict how the warming of the southern oceans would affect their foraging distribution.

The models predict that the penguins' optimum feeding zones (associated with the polar front) will shift south by about 400 km by 2100. This means that the distance the penguins will have to travel to reach their main food sources would double.

This is bad news - unless the birds develop alternative foraging strategies or move to new breeding sites, such a shift in their foraging range would have a negative effect on the Crozet population in the long term. 

Source
Penguins' food goes south, 3 March 2012, Birdwatch

Proceedings of the Royal Society B citation
PĂ©ron, C, Weimerskirch, H and Bost, C-A. 2012. Projected poleward shift of king penguins (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean. Proceedings of the Royal Society B: doi: 10.1098/rspb.2011.2705.

01 March 2012

Lights, camera, Antarctic penguin action!

ANTARCTICA - You might think that living at the ends of the earth would keep you from society's prying eyes. But that isn't the case for Antarctica's remote residents - Adelie penguins.

For the past six summers, cameras set up by scientists from the Australian Antarctic Division have recorded the lives of Adelies nesting near the Australian stations of Mawson, Davis and Casey along the the East Antarctic coast.

This summer, the scientists intend to extend the camera network even further with a camera in Cape Denison in Commonwealth Bay, and eventually want to see an international network of such cameras across Antarctica. To this end, the Australian Antarctic Division has given two cameras to French and US researchers to trial them on the Antarctic Peninsula.

The cameras are solar-powered, so they begin rolling when daylight returns to Antarctica in October. This allows the scientists to see what the penguins are up to long before weather conditions allow them to conduct fieldwork. The cameras then take photos daily until the end of the breeding season, when the darkness comes back and the penguins return to sea. They can operate over a number of years and save the expense of researchers observing the penguins in the field.

"Cameras will give us an idea of breeding success, with daily photographs allowing us to count nests at the beginning of the season and the number of chicks at the end of the season," Australian Antarctic Division ecologist Colin Southwell told AAP.

Dr Southwell and his team will use the data from the camera network along with older surveys and records to build a more definitive picture of changes in the Adelie populations over the past 30 years, and to then use those to explore and identify the drivers of those changes.

Sources
Scientists train cameras on Adelie penguin by Lloyd Jones, 13 January 2012, Ninemsm
Penguin-cam to keep watch on the waddlers by Jo Chandler, 30 December 2011, The Sydney Morning Herald