Tuesday, December 17, 2013

Traffic Jams Lend Insight Into Emperor Penguin Huddle

Emperor penguins maintain the tight huddle that protects them from the harsh conditions of an Antarctic winter with stop-and-go movements like cars in a traffic jam, a new study has shown. (Credit: Daniel Zitterbart)
Dec. 16, 2013 — Emperor penguins maintain the tight huddle that protects them from the harsh conditions of an Antarctic winter with stop-and-go movements like cars in a traffic jam, a new study has shown.
By using a mathematical model that recreated the positions, movements and interactions of individual penguins in a huddle, researchers have revealed that an individual penguin only needs to move 2 cm in any direction for its neighbour to react and also perform a step to stay close to it. 
These movements then flow through the entire huddle like a travelling wave and play a vital role in keeping the huddle as dense as possible to protect the penguins from the cold; the wave also helps smaller huddles merge into larger ones.

The results have been published today, 17 December, in the Institute of Physics and German Physical Society's New Journal of Physics and are accompanied by a video abstract. An advanced set of videos can be viewed here -- http://www.youtube.com/playlist?list=PLx-sGUtkV82eZJHWNyJ4uxPCBtb1GlWgw
In a previous study, the same group of researchers studied time-lapse videos and showed that instead of remaining static, penguins in a huddle actually move every 30-60 seconds, causing surrounding penguins to move with them.

Co-author of the study Daniel Zitterbart, from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), said: "Our previous study showed how penguins use travelling waves to allow movement in a densely packed huddle, but we had no explanation as to how these waves propagate and how they are triggered."

To investigate this, the researchers used a mathematical model, which has previously been used to study traffic jams, and compared the results with an analysis of video recordings of a real-life penguin huddle.
Unlike a traffic jam, the researchers found that the waves of movements in a penguin huddle can originate from any single penguin and can propagate in any direction as soon as a sufficient gap, known as a "threshold distance," develops between two penguins.

This threshold distance was estimated to be around 2 cm, which is twice the thickness of a penguin's compressive feather layer, suggesting the penguins touch each other only slightly when standing in a huddle without compressing the feather layer so as to maximize huddle density without compromising their own insulation.

"We were really surprised that a travelling wave can be triggered by any penguin in a huddle, rather than penguins on the outside trying to push in," continued Zitterbart. "We also found it amazing how two waves, if triggered shortly after each other, merged instead of passing one another, making sure the huddle remains compact."

The emperor penguin is the only vertebrate species that breeds during the severe conditions of the Antarctic winter. At this time of year temperatures can get as low as -50°C and winds can reach speeds of up to 200 km/h.

To cope with the harsh conditions, the male penguins form dense huddles, often consisting of thousands of individuals, to maintain their body temperatures. Unlike other species of penguin, the male emperors are solely responsible for incubating their single egg during the winter, covering it in an abdominal pouch above their feet while the female returns to sea to feed.

Story Source:
The above story is based on materials provided by Institute of Physics, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. R C Gerum, B Fabry, C Metzner, M Beaulieu, A Ancel, D P Zitterbart. The origin of traveling waves in an emperor penguin huddle. New Journal of Physics, 2013; 15 (12): 125022 DOI: 10.1088/1367-2630/15/12/125022

Institute of Physics (2013, December 16). Traffic jams lend insight into emperor penguin huddle. ScienceDaily. Retrieved December 17, 2013, from http://www.sciencedaily.com­ /releases/2013/12/131216204020.htm

Friday, December 13, 2013

2 Profs Head to Antarctica for Penguin Studies

Penguin study

Posted: Dec 12, 2013
  San Diego, California News Station - KFMB Channel 8 - cbs8.com
SAN DIEGO (CBS 8) - Funding is a dilemma researchers always face. Luckily for one local scientist, private funding paved the way from San Diego to the South Pole, with the benefit of using new technology that's cutting down on time in the field with better accuracy. In this week's earth 8 we bring you part 2 of the science behind this penguin study.
Senior research scientist Dr. Brent Stewart hopes to answer many important questions about several penguin species living on the South Pole.

When you're surrounded by hundreds of thousand of birds, the only way to get a better count is to fly high above them. As we showed you in part one of this series, a drone-like aircraft was used to collect more precise scientific data.
"What I really like about it is it can be a stable platform rather than flying over very quickly, we can hover. We can quickly move it in one direction, spin it around to get different perspectives," Stewart said. "But it's going to take another month, two months to count each bird at the two colonies. The big ones, the king penguins St. Andrews Bay, Salsbury Plains, they're probably 200,000 to 300,000 birds at each one of those colonies."

Although it looks crowded, Stewart says some colonies are not doing as well as others.
"Adelie penguins on the peninsula, we know that their populations are changing very rapidly as the climate there changes very rapidly. But other species are coming in and doing very well, so there are local colonies which are sustaining and are vital and other colonies are declining," he said.

Aside from a variable climate, penguins will always have natural predators.
"For Antarctic penguins, leopard seals are predators, they eat them. Particularly in the peninsula, killer whales, I think the ultimate predators are parasites which they're always dealing with. Infectious disease is a key issue in their population, biology. But it's really leopard seals and killer whales are their primary predators other than humans used to be.

"We're starting to plan for the next season next year for the Antarctic trip. Locally it's elephant seal season that's coming up in December, so I spend a lot of time out in San Nicholas & San Miguel Islands to study populations there, and we're trying to use the same kind of tools to help us with that," Stewart said.



Citadal professor headed to Antarctica to study penguins

  • Posted: Thursday, December 12, 2013
A rockhopper penguin warms its young chick and guards against predators during Citadel professor Paul Nolan's 2006 research trip to the Falkland Islands.
Penguins are the proverbial canary in a coal mine when it comes to gauging climate change, says Citadel biology professor Paul Nolan.

So he packed his freezing-weather gear and is headed to Antarctica Friday to study them.

Nolan, who studies animal behavior focusing mostly on birds, said he's been studying penguins for more than a decade, including taking several trips south of the equator to observe the waddling black and white creatures in their natural habitats.

He'll be working on the penguin study with Oxford University professor Tom Hart. People can learn more about the work, at PenguinLifelines.org.

Nolan, who also runs the nonprofit group CharlestonAudubon.org,said The Citadel Foundation gave him a $3,000 grant to help him with his research. He expects to share much of what he experiences with his students in future classes.

Jay Dowd, the foundation's chief executive officer, said Nolan's research is one of many ground-breaking projects conducted on campus by faculty, graduate students, and cadets to which the foundation contributes.
Nolan said it's important to go to Antarctica because "ongoing climate change is most pronounced at the poles." In Antarctica, there's been a 5- to 6-degree temperature increase in the past 100 years," he said.

The researchers plan to study the birds in two major ways. They will collect and analyze feathers that drop from the birds, he said, because feathers contain stress hormones, an indicator of environmental change.
They also will place cameras in penguin colonies that snap pictures every hour. The cameras will remain in place for about a year, he said, then researchers will go back and collect the cards from the cameras and study the photos. "The big idea behind this is that we want to monitor the behavior without bothering the birds."

A huge number of photographs will be collected, Nolan said, and members of the public can volunteer to help annotate them. The photographs will be available on April 25, which is International Penguin Day, he said.

Nolan said his unique role in the project is to study the color and color changes of the birds, especially in their beaks and feet. Color can reveal a great deal about an animal's health, he said.

Temperatures in Antarctica this time of year range from 0 to 20 degrees, he said, but he's ready for the cold.
The research team will travel on a cruise ship, and take Zodiac boats to various penguin colonies each day, he said. It's very difficult to find a way to travel in that part of the world, he said, but cruise ships work well. The researchers will make some presentations on penguins to other travelers, he said.


A Penguin's Tale: Diet Linked to Breeding Failure

Dec. 12, 2013 — A study on a Victorian penguin colony has revealed new insight into the link between seabird diet and breeding success.

In a study published in Functional Ecology, Nicole Kowalczyk and Associate Professor Richard Reina of Monash University's School of Biological Sciences, in collaboration with Andre Chradia from Phillip Island Nature Parks, studied Melbourne's St Kilda little penguin colony over two years.

They detailed how changes to prey abundance or food sources influenced reproductive success, tracking the penguins' nesting and feeding behaviour during the 2010 and 2011 breeding season.

Given previous data had shown that the colony fed mainly on anchovy which accounted for up to 78 per cent of their diet between years 2004 and 2008, the researchers predicted that changes in abundance would impact on the reproductive success of the colony -- but they were surprised to find the little penguins were resilient to changing conditions only if alternative prey such as sardines could be found.

Ms Kowalczyk said breeding failure in seabirds has been associated with declines in prey abundance, and the quality and diversity of prey -- but identifying which aspect of diet was responsible was challenging.
"The St Kilda little penguin colony has a short foraging range and displays narrow dietary diversity so this gave us the unique ability to identify how changes in food supply influence their reproduction," Ms Kowalczyk said.

"We found that a sharp decline of anchovy in 2010 had a negative impact on little penguin reproduction. However, in 2011, despite the relatively low anchovy abundance, their breeding success was extremely high.
"We believe the decrease of anchovy itself was not the only cause for low breeding success in 2010 but in combination with the scarcity of alternative prey. Our results show that little penguins are resilient to changes in their preferred prey but their ability to adapt to these changes is limited by the availability of alternative prey species."

Ms Kowalczyk said understanding seabird diet was integral to their conservation and management.
"Our results highlight that resource abundance and the availability of a variety of prey are critical factors in enabling this inshore seabird to adjust to changes in environmental conditions and fluctuations in their primary source of prey," Ms Kowalczyk said.

"Dietary changes have been linked to population declines and provide information about foraging conditions, particular prey species and foraging locations that require protection."

Story Source:
The above story is based on materials provided by Monash University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Nicole D. Kowalczyk, Andre Chiaradia, Tiana J. Preston, Richard D. Reina. Linking dietary shifts and reproductive failure in seabirds: a stable isotope approach. Functional Ecology, 2013; DOI: 10.1111/1365-2435.12216

Monash University (2013, December 12). A penguin's tale: Diet linked to breeding failure. ScienceDaily. Retrieved December 13, 2013, from http://www.sciencedaily.com­ /releases/2013/12/131212103351.htm