Mass bird deaths rare, not apocalyptic: experts

OSLO Thu Jan 6, 2011 1:15pm EST

One of thousands of blackbirds that fell out of the sky on New Year's Eve lies on the ground in Beebe, Arkansas, January 1, 2011. REUTERS/Arkansas Game and Fish Commission/Handout

One of thousands of blackbirds that fell out of the sky on New Year's Eve lies on the ground in Beebe, Arkansas, January 1, 2011.

Credit: Reuters/Arkansas Game and Fish Commission/Handout

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OSLO (Reuters) - Birds falling out of the sky in the United States and Sweden are freak examples of the kind of mass animal deaths, from beached whales to deluges of frogs, that have unusual but not apocalyptic causes, experts say.

Storms, hail or lightning can kill birds while tornadoes or waterspouts may suck up small fish or frogs and drop them far away. Human causes, such as fireworks, power lines or a collision with a truck, may explain avian deaths.

The U.N. Environment Program (UNEP) urged more research into baffling deaths -- ranging from why whales sometimes make the fatal mistake of swimming onto beaches to recent bird deaths, dubbed the "Aflockalypse" by one newspaper.

"Science is struggling to explain these things. These are examples of the surprises that nature can still bring," said Nick Nuttall, spokesman of Nairobi-based UNEP. "More research is needed."

Modern threats such as pollution or climate change may be adding to background stresses on wildlife.

About 500 dead birds were discovered in Louisiana this week and 5,000 in Arkansas at New Year, many of them red-winged blackbirds. Swedish authorities have been investigating the deaths of 100 jackdaws found in a street in Falkoping.

"We made an autopsy on five of the birds yesterday and found internal bleeding but no external lesions," said Marianne Elvander of Sweden's National Veterinary Institute.

NO BIRD FLU

She said there was no sign that they had died from diseases such as bird flu -- the main worry in such cases. Among the theories was that a truck had collided with the flock.

In Beebe, Arkansas, one theory is that fireworks spooked the birds to fly into buildings or other objects. Such birds roost in vast numbers, fly fast and have poor night eyesight, Nuttall said.

The widely publicized deaths meant other incidents received far more attention than they otherwise would have. "This is a classic example of freak events coinciding," said Petter Boeckman, a zoologist at the Norwegian Natural History Museum.

He said mass deaths of birds were not unheard of, but they normally happened unnoticed at sea or in rural areas away from towns. Many birds are weak and die in winter when food is scarce.

In one infamous example, 60,000 ducks died in the Baltic Sea in 1976 after they landed on a small oil slick, fatally mistaking it for an attractive patch of calm water.

Storms that suck up small creatures have been linked to reports of small perch fish falling out of the sky in Australia in 2010 far from open water and to a hail of frogs in northwestern Serbia in 2005. Lemmings often die en masse when food runs short.

Whale beachings might be caused by factors such as illness, or disorientation caused by extra noise in the oceans, from shipping or oil and gas drilling.

Boeckman said the response to the bird deaths also illustrated differences between more religious-minded Americans, versed in Biblical accounts of plagues of frogs or locusts, and secular Swedes who place their trust in human authority.

"In the United States the reaction is 'oh no, Doomsday is coming'. In Sweden, they say 'let's call the veterinary authorities'," he said.

For Reuters latest environment blogs, click on: blogs.reuters.com/environment/

(Editing by Noah Barkin)

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Comments (14)
gordon77 wrote:
Mangnetic field shift. Earth’s magnetic field extends thousands of miles into space and shields surface life from the solar wind—a potentially harmful stream of charged particles emanating from the sun.

Jan 06, 2011 10:33am EST  --  Report as abuse
Jusaf2 wrote:
Studies have showed that the earth’s electro magnetic shield is weakening at an alarming rate. Other studies show that fish, birds, and other animals use the electro magnetic shield to navigate and migrate around the world. Has anyone studied the weakening shield’s effect as it relates to these events? If not, why not?

Jan 06, 2011 10:38am EST  --  Report as abuse
Bionic wrote:
Here is what I assume to know from the Arkansas event:

Given the time of year these birds normally would be roosting at the time this occurred. Something made them leave their roost.

Birds were flying or in the air when the life ending injuries occurred.

And due to air resistance on feathers slowing the decent it is assumed that the falling birds suffered internal injuries prior to hitting the ground.

Questions –
Were any of the birds on the ground simply injured and moving a bit before expiring? Or did they suffer a massive life ending trauma in the sky and then fall to earth?

Were birds scattered about across the mile radius or found around structures like houses, water towers, trees etc?

If there was an even distribution over the mile area where birds were found then could it be assumed that the birds were carried to a much higher elevation than normal – thus allowing for a greater dispersion over the ground area?

Regarding injuries: I would think that even in a dense flock of panicked birds the odds that two would fly into one another in such a way to cause death to one or both birds would be great. In fact in the dark how do they know to even stay in a “flock”. So if they were startled and simply flying in a chaotic non organized way the birds were even more likely to not crash into one another.

This leads me to believe that during the earlier storms or around the time of the storms normally flocking birds from one area were sucked into a massive thermal updraft or vortex not unlike a tornado, funneling them into a churning dense mass where they collided with one another mortally injuring them, then taking them extremely high into the atmosphere where they rode the thermals until they were displaced over a large area.

Last question – did they think to GPS mark where each bird was found so we could study the dispersion pattern on Google Earth, etc?

Jan 06, 2011 11:23am EST  --  Report as abuse
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