Thursday, June 14, 2007

Some Common Birds Not So Common Anymore

The populations of 20 common American birds - from the fence-sitting meadowlark to the whippoorwill with its haunting call - are half what they were 40 years ago, according to an analysis released Thursday.

For the study, researchers looked at bird populations of more than half a million which covered a wide range. They compared databases for 550 species from two different bird surveys - the Audubon's own Christmas bird count and the U.S. Geological Survey's breeding bird survey in June. The numbers of 20 different birds were at least half what they were in 1967.

Today there are 432 million fewer of these bird species, including the northern pintail, greater scaup, boreal chickadee, common tern, loggerhead shrike, field sparrow, grasshopper sparrow, snow bunting, black-throated sparrow, lark sparrow, common grackle, American bittern, horned lark, little blue heron and ruffed grouse.

Suburban sprawl, climate change and other invasive species are largely to blame, said the study's author Greg Butcher of the National Audubon Society.
I have called for a species census to find out information such as this on all species. These bird watchers collect great data, but we should expand this kind of data to as many species as we can.

Just because a species is not endangered, doesn't mean its populations aren't dropping drastically. And it might make more sense to focus on stopping population loses of these species rather than trying to keep a species with a tiny population from extinction.

The news is not all bad. There are winners as well as losers.
While these common birds are in decline, others are taking their place or even elbowing them aside. The wild turkey, once in deep trouble, is growing at a rate of 14 percent a year. The double-crested cormorant, pushed nearly to extinction by DDT, is growing at a rate of 8 percent a year and populations of the pesky Canada goose increase by 7 percent yearly.

Many of the birds that are disappearing are specialists, while the thriving ones are generalists that do well in urban sprawl and all kinds of environments, Butcher said. In a way it's the Wal-Mart-ization of America's skies, he said.

"Right now the Eurasian collared-dove is conquering America," Butcher said. A dove-like bird that first entered Florida in the 1980s, it now is the most prevalent bird in the Sunshine State and is in more than 30 states.
via Wired


Audacious Epigone said...

I think the study you are referring to is the same one I posted on last month, although if so the "Walmart" comment doesn't really make sense (although as I've written previously, generally that has been, is, and will continue to be the trend).

I'm an order of magnitude more concerned with the decimation of our ornothological pals from other-continental diseases. A significant reduction in the crow population has the potential to actually be felt at several levels, whereas a disappearnce of the Snail Kite, while tragic, is inconsequential.

Fat Knowledge said...


I believe this is a different study that just came out, I'm not certain on that.

You are probably right on the impact of viruses, I don't know enough to say.

I think you bring up a good point with the impact of a loss of crows vs. Snail Kites. Some species play a more important role in ecosystems, and are much more valuable to preserve than others that are so specialized that they can disappear with no impact on the ecosystem. I wish there was more research done on this, so we would know which species are most important to protect.

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