Latest BBC Climate Classic – The Birds Are Shrinking!

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8560000/8560694.stm

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.

“On average, the decline in mass of spring migrants over the 46 year study was just 1.3%,” says Dr Buskirk.

“For a 10g warbler that’s a loss of just 130mg.”

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The article then finishes with a nice little “you ignorant fools” sentence…..

“For example, it took an avalanche of data before people became convinced that climate change is already altering when birds start migrating.”

Now I am no expert in birds or their migration patterns.  However I would suggest that we have only been able to accurately study migration patterns within the past 100 years.  So how do we know that changing migration patterns have not always occurred and for a variety of reasons?  What makes it so certain that migration is set in stone?  If the birds in this article can evolve physically in 20 generations, then surely their migration patterns are unlikely to remain static and to be equally sensitive?

So is this unprecedented, unusual or dangerous?

This is also not a new finding, it was reported in Australia a while back:

http://www.physorg.com/news169377749.html

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The climate always changes, and evidently so do the birds.  Which takes us right back to the start of the loop to say, yes we all know the climate is changing, it always has and always will.

But is what is happening now, unprecedented,  or even unusual in its rapidity and effects? For me the answer is still very much, no, and I don’t think anyone can yet prove conclusively otherwise.

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