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DISPLAYING POSTS BY: Karen Rowe (2)

Penguin Awareness Day

Author
by Karen Rowe
Publish date
20 January 2012
Comments
Comments (1)

Karen Rowe is a Research Associate at MV where she studies evolutionary ecology and behaviour in birds and mammals.

January 20th is an auspicious day for birding enthusiasts, marking Penguin Awareness Day. With 17 species currently recognised, members of the family Spheniscidae (pronounced sfen-IS-kuh-dee) are found only within the southern hemisphere. While most of us think of penguins as cold-adapted animals, surviving long treks over ice to breed and raise their young in the middle of winter, many species live further north, among the islands off of Antarctica, along the coasts of New Zealand and Australia, and one species is found on the Galapagos Islands (the aptly named Galapagos Penguin).

Royal Penguins Royal Penguins (Eudyptes schlegeli) – among Elephant Seals on Macquarie Island.
Image: Julie McInnes
Source: Julie McInnes
 

As a group, penguins possess an amazing array of adaptations, uniquely suited to their predominately marine existence. Unlike other birds, penguins have solid, rather than air-filled bones, to help them dive in the water. They have highly modified feathers that form a thick insulating layer that cover the body, rather than growing in the well-defined feather tract found in other birds. They also have unique eyes that allow them to see clearly both on land and in the sea. And while their short legs and feet make them seem awkward on land, many species actually travel tremendous distances over land and rocks to reach their breeding sites – some even traveling as far as three kilometres from water.

Magellanic Penguin Captive Magellanic Penguin (Spheniscus magellanicus) floating in the water. The coloured flipper band allows zoo keepers to distinguish between individuals.
Image: Erich Fitzgerald
Source: Museum Victoria
 

Extant species show a wide range of body sizes, from our own Little (or Fairy) Penguins, weighing 1.1 kg and standing 40 cm tall, to the largest species, the Emperor Penguin, at a whopping 30 kg and up to 115 cm tall.

Little Penguins Little Penguins (Eudyptyla minor) in captivity. These coloured leg bands are another way to tell individuals apart.
Image: Erich Fitzgerald
Source: Museum Victoria
 

But even the Emperor Penguin is dwarfed in size by some of the extinct fossil penguins, including a 15-million-year-old giant penguin (Anthropodyptes gilli) from Victoria that may have approached twice its size. Senior Curator of Vertebrate Palaeontology, Dr. Erich Fitzgerald studies fossil penguins here at Museum Victoria. "Victoria was home to a remarkable diversity of penguins over the last 20 million years," says Dr. Fitzgerald. "The tiny Little Penguin living in Australia today is an oddity on a geologic timescale. The fossil record tells us that most penguins that have lived in Australia were large to huge in size and that at any one time there were perhaps two or more species coexisting here." Currently, Dr. Fitzgerald and his student, Travis Park, are working on six-million-year-old fossil penguins found in Melbourne on the shores of Port Philip Bay that are thought to be the size of the living Gentoo and Emperor Penguins.

Penguin limb bones The upper wing bone (humerus) of living penguins compared with their fossil counterparts from Victoria. From left to right: the 18-million-year-old fossil Anthropodyptes gilli; the living emperor penguin Aptenodytes forsteri; the living fairy penguin Eudyptula minor; the living gentoo penguin Pygoscelis papua; and the 6-million-year-old fossil Pseudaptenodytes. Credit: Photograph by Erich Fitzgerald
Image: Erich Fitzgerald
Source: Museum Victoria
 

Emperor Penguin and chick Emperor Penguin and chick, Antarctica.
Image: Julie McInnes
Source: Julie McInnes
 

The unique ecology of penguins makes them particularly susceptible to a variety of human-induced threats. In particular, commercial fishing, often leading to death through by-catch or competition for prey items (which include fish, crustaceans, and cephalopods), directly impacts their survival. Penguins are also dependent on breeding grounds close to the shore and habitat loss is a major source of population declines. Smaller and fewer breeding grounds also promotes disease, as most species of penguins breed in large colonies.

Royal Penguin colony Royal Penguin colony. This species is endemic to Macquarie Island and this is the largest Royal Penguin colony with over 180,000 breeding pairs. The fluffy young penguin in the front on the right is in moult.
Image: Julie McInnes
Source: Julie McInnes
 

Although little research has been done looking at the impact of climate change on penguins, their specialised lifestyle suggests that climate change could have dramatic impacts on their distribution and abundance. "Penguins are an ancient group of birds, with a history stretching back some 65 million years to the extinction of the dinosaurs," says Dr. Fitzgerald. "In southern Australia they have persisted through the last 20 million years of major climatic changes, but it is unknown how they will respond to the current human-exacerbated wave of environmental upheaval. It would be a terrible shame to see this ancient and superbly successful group of birds become threatened with extinction within our lifetime."

Adelie Penguin, Bechervaise Island, Antarctica. Adelie Penguin, Bechervaise Island, Antarctica.
Image: Julie McInnes
Source: Julie McInnes
 

Links:

Emperor Penguins in the Wild: Amazing animals in a changing world

Penguins on Atlas of Living Australia

Happy Feet Two at IMAX Melbourne

Desert rains trigger rat plagues

Author
by Karen Rowe
Publish date
3 August 2011
Comments
Comments (3)

Karen Rowe is a Research Associate at MV where she studies evolutionary ecology and behaviour in birds and mammals.

Record levels of rainfall in the Northern Territory have brought forth one of Australia’s rare and unique native mammals, the Long-haired, or Plague Rat (Rattus villosissimus). These herbivorous rats feed largely on stems and leaves and, with consistently high rainfall, large areas of the desert landscape have become lush with food. Coupled with an unusually high reproductive rate, where a single female can produce more than 200 young in one year, these rats are capable of large-scale population explosions leading to rapid dispersal over huge distances. They have even been documented moving as much as 3 km in a single night.

In the past, these rodents have spread across the arid regions of Australia, including eastern Western Australia, the Northern Territory, eastern Queensland and parts of South Australia. Historic plagues have been documented as far back as 1847, with others occurring in 1916-18, 1930-32, 1940-42, 1948, 1950-52, 1956, and 1966-69.

Once the plague recedes, they vanish almost as quickly as they arrived and during non-plague years, they become rare and hard to find, persisting in only a few locations.

Taking advantage of this unique opportunity to document the latest plague, I joined MV mammal curator, Kevin Rowe, and collections manager, Wayne Longmore, to try to find these rats in the Northern Territory, along the Finke River.

Kevin Rowe and Wayne Longmore MV curator, Kevin Rowe (left), and collections manager, Wayne Longmore (right), trapping rats in the desert rain.
Image: Karen Rowe
Source: Karen Rowe
 

We found them in abundance – nearly all of our live traps contained a long-haired rat, and one had two!

Rattus villosissimus caught along the Finke River Rattus villosissimus caught along the Finke River.
Image: Karen Rowe
Source: Karen Rowe
 

We even found part of the skeleton of one in a bird pellet – the undigested material regurgitated by a bird, particularly in birds of prey.

Bird pellet before dissection Bird pellet before dissection.
Image: Karen Rowe
Source: Karen Rowe
 

Bird pellet after dissection After dissection – most of the skull and jaw were intact (on left).
Image: Karen Rowe
Source: Karen Rowe
 

Long-haired rats build burrows in the sand, consisting of meters of tunnels with multiple entrances and exits. They use these burrows extensively, spending nearly 80% of their time underground.

Rattus villosissimus burrow entrance Rattus villosissimus burrow entrance.
Image: Karen Rowe
Source: Karen Rowe
 

At the Finke River site, the sandy soil made it easy to see footprints into and out of these burrows.

Rattus villosissimus footprints Rattus villosissimus footprints.
Image: Karen Rowe
Source: Karen Rowe
 

Kevin and Wayne are still on the hunt for the plague rat, hoping to find more populations in the Barkly Tablelands and central NT. By studying these rats from throughout the state and recording natural history data such as behaviour and habitat, as well as traits of the rats themselves, including age and reproductive state, we can better understand the ecology and biology of this unique, native, and (most of the time!) rare mammal.

Links:

MV Blog: On rats

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