WASHINGTON, Feb. 10, 2009
As Planet Warms, Bird Species Move North
Survey: Half Of Bird Species Spend Winter Further North Than They Did 40 Years Ago
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Play CBS Video Video Birds Travel North For Winter According to a report, many species of birds are responding to increasing climate change by traveling north instead of south. John Blackstone reports.
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The black-bellied plover, a shorebird, is spending its winters 114 miles further north than it did four decades ago, according to an analysis of survey data collected by the National Audubon Society. (USFWS, Tim Bowman)
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Interactive Global Warming The greenhouse effect, a look at the Kyoto Protocol and a history of the Earth's climate.
As the temperature across the U.S. has gotten warmer, the purple finch has been spending its winters more than 400 miles farther north than it used to.
And it's not alone.
An Audubon Society study to be released Tuesday found that more than half of 305 bird species in North America - a hodgepodge that includes robins, gulls, chickadees and owls - are spending the winter about 35 miles farther north than they did 40 years ago.
The purple finch was the biggest northward mover. Its wintering grounds are now more along the latitude of Milwaukee, Wis., instead of Springfield, Mo.
Bird ranges can expand and shift for many reasons, among them urban sprawl, deforestation and the supplemental diet provided by backyard feeders. But researchers say the only explanation for why so many birds over such a broad area are wintering in more northern locales is global warming.
Over the 40 years covered by the study, the average January temperature in the United States climbed by about 5 degrees Fahrenheit. That warming was most pronounced in northern states, which have already recorded an influx of more southern species and could see some northern species retreat into Canada as ranges shift.
"This is as close as science at this scale gets to proof," said Greg Butcher, the lead scientist on the study and the director of bird conservation at the Audubon Society. "It is not what each of these individual birds did. It is the wide diversity of birds that suggests it has something to do with temperature, rather than ecology."
The study provides compelling evidence for what many birders across the country have long recognized - that many birds are responding to climate change by shifting farther north.
Previous studies of breeding birds in Great Britain and the eastern U.S. have detected similar trends. But the Audubon study covers a broader area and includes many more species.
The study of migration habits from 1966 through 2005 found about one-fourth of the species have moved farther south. But the number moving northward - 177 species - is twice that.
As average January temperatures rose more than 5°F in the continental U.S. over the past 40 years (left), the mean latitude marking the center of abundance for 305 North American bird species has moved 35 miles north during the same time.(National Audubon Society)
The research is based on data collected during the Audubon Society's Christmas Bird Count in early winter. At that time of year, temperature is the primary driver for where birds go and whether they live or die. To survive the cold, birds need to eat enough during the day to have the energy needed to shiver throughout the night.
Milder winters mean the birds don't need to expend as much energy shivering, and can get by eating less food in the day.
General biology aside, the research can't explain why particular species are moving. That's because changes in temperature affect different birds in different ways.
Some birds will expand their range farther north. For example, the Carolina wren - the state bird of South Carolina - has turned into a Yankee, based on Audubon's calculations. It is now commonly seen in the winter well into New England, as well as its namesake state of South Carolina.
"Twenty years ago, I remember people driving hours to see the one Carolina wren in the state," said Jeff Wells, an ornithologist based in southern Maine. "Now, every year I get two or three just in my area," he said. "Obviously, things have changed."
Fast Fact
Other species, such as the purple finch and boreal chickadee, spend their summers in the forests of Canada and fly south into the U.S. for the winter. Climate change could be playing a role in why they are not flying as far south as they used to, and are no longer as common as they were in states like Maine, Vermont and Wisconsin.
South Carolina's state bird, the Carolina wren, can now be found spending winters in New England.
For other species, global warming may not be a major factor in the movements measured by Audubon at all. The wild turkey was second only to the purple finch in miles moved north - about 400. But it's likely due to efforts by hunters and state wildlife managers to boost its population.
In other cases, the range shifts are prompting calls to cull some bird populations.
The sandhill crane, a large gray bird that migrates to the southern U.S. for the winter, has a range that expanded about 40 miles north in the last 40 years. This small movement has likely contributed to the bird's population explosion in Tennessee. The sandhill population has grown to a point that state wildlife officials are considering allowing the bird to be hunted.
"You are seeing it all across the state," said Richard Connors, president of the Tennessee Ornithological Society. "As it increases, there is going to be pressure to hunt it. The bird watchers of Tennessee don't want that."
For more info:
By Associated Press Writer Dina Cappiello
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Add a Comment See all 58 Comments
- I just thought of something I have never eaten goose. Go figure
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Posted by lewiston14
Not a bad-tasting bird! Watch it cook and you will be amazed at the amounts of fat it has.... Go ahead and try a goose - before that too is extinct! - Reply to this comment
- "So what was extra fun for a bunch of sea-birds back then is going to be the greatest natural disaster EVER today with tens of millions of people homeless. You still say that nothing should be done - that slowing the process down, if we can, is not a good aim?"
I suppose we could stop solar flares.... Don''t know how, I''m just the "idea guy". Maybe we could get the "experts" from the ''70''s who scared us all by insisting that glaciers would cover Manhattan if we did not stop emissions to figure that one out. - Reply to this comment
- I find it very interesting that there is no mention of the birds that are coming south? Shouldn''t they be going further into the arctic and not coming down south? How can that be? Where is the logic?
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- Posted by AJMarine111 at 07:40 PM : Feb 10, 2009
I thank you for the information, you obviously have studied your English history. You will have also heard of the "Cinque Ports" along the south coast, Hastings, New Romney, Hythe, Dover, and Sandwich. Of these New Romney and its neighbours Rye and Winchelsea, all important achorages in the 1100''s are now two or three miles inland. This is partially due to the silting up of the nearby Romney Marsh, but the sea has also retreated. Yes, obviously there have been warmer periods in history (see also my 9:19 post). But to say the one or two cold winters or a couple of hot summers are evidence pro or con GW is nonsense. You have to go by trends over time, and the current trend is upwards. The debate should be is the rise faster than what''s been seen in the past, and most of the evidence at this point says "YES." - Reply to this comment
- After all, it can''''t possibly be caused by solar activity fluctuations or any other natural cause, right?
Posted by motard117
OK, OK, OK - so the earth has been warm before. However, the populations of Manhattan, Miami and New Orleans back around 1100 were a tiny bit smaaller than they are today. So what was extra fun for a bunch of sea-birds back then is going to be the greatest natural disaster EVER today with tens of millions of people homeless. You still say that nothing should be done - that slowing the process down, if we can, is not a good aim? - Reply to this comment
- Oh no! Is it really getting warmer? That''s never happened before in the history of the Earth! Wait, I think I do remember reading something about greenhouse gases from right-wing oil companies causing the glaciers to recede several thousand years ago. After all, it can''t possibly be caused by solar activity fluctuations or any other natural cause, right?
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- There were tornados in Oklahoma today -- global warming.
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- It snows more at 26 degrees than at 15...just another sign of warming
Posted by bobbyduck1 at 06:52 PM : Feb 10, 2009
Especially when it''s colder than normal. That''s another sign of warming. - Reply to this comment
- Talk about closed minded. I tell you something based in pure science and you call me closed minded. You are the one that has blinders on dickwad. Tell me how humans have th audicity to think they can control what we are doing well enough to be able to stop what has been done to it. Come on idiot. Tell how this will happen. Give me the science.
Posted by ihateislam at 07:31 PM : Feb 10, 2009
Al Gore and many others have done so repeatedly - but too many treat it as a left-wing conspiracy. It''s to the point where ANYONE with the sense to see what''s happening before our eyes is immediately labelled by the right wing, "corporate bottom line is all that matters" bunch of neo-whacks that drink too much of Rush Bimbo''s kool-aid.
Now I''ve wasted enough of my time on you. Goodbye - Reply to this comment
- How exactly do the believers measure ice thickness and geese flight routes? How ridiculous and gullible believers are! Posted by Mihann
WHY DON''T YOU DO SOME RESEARCH AND LOOK IT UP INSTEAD OF BEING SO IGNORANT; MAYBE YOU''LL LEARN SOMETHING... - Reply to this comment
- One other sign of a gentle warming going on - forty years ago you couldn''''t grow grapes in England. Now there are vinyards in Yorkshire, 200 miles north of the Channel.
Posted by usclimey at 07:08 PM : Feb 10, 2009
At the time of the compilation of the Domesday Survey in the late eleventh century, vineyards were recorded in 46 places in southern England, from East Anglia through to modern-day Somerset. By the time King Henry VIIIth ascended the throne there were 139 sizeable vineyards in England and Wales - 11 of them owned by the Crown, 67 by noble families and 52 by the church.
It is not exactly clear why the number of vineyards declined subsequently. Some have put it down to an adverse change in the weather which made an uncertain enterprise even more problematic. Others have linked it with the dissolution of the monasteries by Henry VIII. Both these factors may have had some part to play but in all probability the decline was gradual (over several centuries) and for more complex reasons - Reply to this comment
- The finch moved further north by 400 miles. Other birds migrated a whole 35 miles?! In 40 years no less. Now that IS impressive. You guys are going to have to do better than that to prove global warming. That''''s not even scary.
Posted by scottyusa at 07:03 PM :
Alright then, let''s have you walk across a lake in Iowa in January, 30 years ago you could - Reply to this comment
Posted by yellow651 at 05:56 PM : Feb 10, 2009
Yes, you are in part so correct.
They should open their eyes, and look at the world around them, then they would see that there is little doubt of the credible climate scientists [the vast majority] being correct, this world is indeed in trouble, there are so many climate connected catastrophe''s continually happening, that surely the most ardent denier must soon admit they are possibly wrong.
Climate change is not necessarily always indicated by heating, as we have seen by the extraordinary weather events throughout the world, it is evidenced in the many abnormal such events.- Reply to this comment
- One other sign of a gentle warming going on - forty years ago you couldn''t grow grapes in England. Now there are vinyards in Yorkshire, 200 miles north of the Channel.
- Reply to this comment
- How exactly do the believers measure ice thickness and geese flight routes? How ridiculous and gullible believers are!
Posted by Mihann
It''s called observation using open eyes as opposed to blind ignorance with closed minds. - Reply to this comment
- The finch moved further north by 400 miles. Other birds migrated a whole 35 miles?! In 40 years no less. Now that IS impressive. You guys are going to have to do better than that to prove global warming. That''s not even scary.
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- It is too late to make the short term changes to our environment to make a difference in less than 10,000 years. People better wake up to this fact and stop wasting money trying to fix this and start adapting life styles to ensure that when the water rises you are not living on the coastline when it happens.
Posted by ihateislam at 06:08 PM : Feb 10, 2009
Sure, that''s it. Bury our heads in the sand, shrug our shoulders and ruin what''s left for our grandkids. That''ll help. Sounds as closeminded as your embicilic screen-name - gee you wouldn''t be a neo-wack right-winger would you? - Reply to this comment
- Last year, Michigan had almost 50 percent more snow than average. This year it''''s on a pace to beat that. The birds ain''''t coming to Michigan.
Posted by sMT451D at 05:46 PM : Feb 10, 2009
It snows more at 26 degrees than at 15...just another sign of warming - Reply to this comment
- This is another validation of what climate scientists have been telling us. Science has a way of prevailing over prejudice and delusion.
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- We are less than 200 miles from the Canadian border and have birds all year long here. That did not happen even 20 years ago. Either the birds have become cold tolerant or the temperatures just aren''t as cold...
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The road ahead in Afghanistan, and the crucial decision Obama faces.
