Posted on 03/12/2010 10:55:45 AM PST by NormsRevenge
Songbirds in the US are getting smaller, and climate change is suspected as the cause.
A study of almost half a million birds, belonging to over 100 species, shows that many are gradually becoming lighter and growing shorter wings.
This shrinkage has occurred within just half a century, with the birds thought to be evolving into a smaller size in response to warmer temperatures.
However, there is little evidence that the change is harmful to the birds.
Details of the discovery are published in the journal Oikos.
In biology, there is a general rule of thumb that animals tend to become smaller in warmer climates: an idea known as Bergman's Rule.
Usually this trend can be seen among animal species that live over a range of latitude or altitude, with individuals living at more northern latitudes or higher up cooler mountains being slightly larger than those below, for example.
Quite why this happens is not clear, but it prompted one group of scientists to ask the question: would animals respond in the same way to climate change?
To find out, Dr Josh Van Buskirk of the University of Zurich, Switzerland and colleagues Mr Robert Mulvihill and Mr Robert Leberman of the Carnegie Museum of Natural History in Rector, Pennsylvania, US decided to evaluate the sizes of hundreds of thousands of birds that pass through the Carnegie Museum's Powdermill ringing station, also in Pennsylvania.
They examined the records of 486,000 individual birds that had been caught and measured at the ringing station from 1961 to 2007.
(Excerpt) Read more at news.bbc.co.uk ...
Chortle!
Nice one. Did this latest BS come from the University of East Anglia too?
So hummingbirds used to be bigger?
It made some birds become foxes and one bird became a deer.
Hold muh beer while I watch the birds shrinking.
The university experts told me so. My taxes paid for their research grants so I’m proud of them!!!!
"It's climate change!"
Birds are shrinking? Watts up with that?
imagine hummers with 6 foot wingspans. :-)
Warmer air and higher humidity leads to less air density, should not lead to smaller wings.
Plus, let’s see “bird size” data from the warm period called The Medieval Warm Period. Called that by everyone except the UN Warmists, who took the inconvenient warmth off their database.
There is also the theory: Economy of purpose!
When the food supply is abundant they don’t have so far to travel to eat - don’t need wide bodies. When the food supply is scarce their metabolism needs to be fast.
After I give it some more thought, I’ll research it and let you know what I find. It helps to have an open mind or an empty one.
Hahahahahahahahahahahaha!
Cool, so BBC, why the heck should anyone care? It can’t be controlled in any form by us.
...and the “bird killer” wind turbines will finish the job, thanks to the hypocrite environmentalists.
Alternative theory: natural selection due to the increased presence of large glass-walled buildings in urban environments. Small birds maneuver more easily, are faster, and tend to smash into reflective glass panels less frequently. I have just as much evidence to prove my theory as they do theirs.
The government solution to this is to make your wallet and income shrink.
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