Mating March of the Penguin Slows Down

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Mating March of the Penguin Slows Down

 

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http://news./s/space/20060403/sc_space/matingmarchofthepenguinslowsdown

 

Bjorn Carey

LiveScience Staff Writer

LiveScience.com Mon Apr 3, 6:02 PM ET

 

Penguins and other Antarctic seabirds are nesting and

laying their eggs later than they did 50 years ago, a

response, scientists say, to global climate change.

 

 

While the effects of climate change on animal behavior

have been well documented in the Northern Hemisphere,

the effects are less well known south of the equator.

In North America and Europe, cold-weather animals are

generally shifting northward as the Arctic warms and

the ice cap shrinks.

 

A new study by two scientists at the Centre National

de la Recherche Scientifique in France compiled data

for Antarctic seabird nesting from 1950 to 2004. It

reveals that nine species of birds are, on average,

arriving nine days later to nest. The birds are also

laying their eggs two days later.

 

Upside down

 

This runs opposite to shifts in avian habits in the

Northern Hemisphere, where earlier springs and

increased food availability has led to birds migrating

and laying eggs earlier in the season.

 

In Antarctica, the delay appears to be tied to sea

ice.

 

Unlike western Antarctica, no major warming or cooling

has occurred in eastern Antarctica since the 1950's.

However, in eastern Antarctica, sea-ice range has

reduced 12 to 20 percent since the 1950's, owing to

global warming, scientists say. Yet localized cooling

has caused the sea-ice season to increase by more than

40 days since the 1970's.

 

These changes have been associated with a decline in

abundances of krill and other marine organisms that

are food resources for most Antarctic seabirds.

 

This may partly explain the delay in seabirds' arrival

and laying dates, the researchers say, since seabirds

need more time to build up the reserves necessary for

breeding.

 

Get to it

 

The shift represents a seven-day compression of the

prelaying period when birds set up territories, court,

and females make their eggs, suggesting that the

birds' reproductive processes have some plasticity.

 

However, the scientists caution, if the seabirds

continue to become less synchronized with their food

source, and the sea ice continues to block their

nesting sites, these species could suffer if they fail

to respond appropriately, either through

microevolution or behavior changes, to climate change.

 

This study is detailed in the April 3 online edition

of the Proceedings of the

National Academy of Sciences. The species affected:

emperor penguin, Adelie penguin, southern giant

petrel, southern fulmar, Antarctic petrel, Cape

petrel, snow petrel, Wilson's storm petrel and the

south polar skua.

 

* Penguin Shuffle: The Next Rage?

* Shifting Icebergs May Have Forced Penguin

Evolution

* How Global Warming is Changing the Wild Kingdom

* Animals and Plants Adapting to Climate Change

* More Frogs Dying as Planet Warms