Two years ago, it was “Study says global warming shrinks birds” now thanks to impressive further study, they’ve discovered it’s “Bigger birds in central California, courtesy of global climate change.“
Can’t they get their story straight? Why don’t they ask Jim Henson Hansen?
From San Francisco State University
Bigger birds in central California, courtesy of global climate change
SAN FRANCISCO — Birds are getting bigger in central California, and that was a big surprise for Rae Goodman and her colleagues.
Goodman uncovered the trend while working as a graduate student for San Francisco State University biologist Gretchen LeBuhn, analyzing data from thousands of birds caught and released each year at two sites near San Francisco Bay and the Point Reyes National Seashore.
The SF State scientists, working with researchers from PRBO Conservation Science and the San Francisco Bay Bird Observatory who collected the data, found that birds’ wings have grown longer and birds are increasing in mass over the last 27 to 40 years.
What’s making the birds bigger? The researchers think that the trend is due to climate change, but their findings put a twist in the usual thinking about climate change and body size. A well-known ecological rule, called Bergmann’s Rule, states that animals tend to be larger at higher latitudes. One reason for this rule might be that larger animals conserve body heat better, allowing them to thrive in the generally colder climate of higher latitudes.
Under this reasoning, some scientists have predicted that animals would get smaller as the Earth has warmed up over the past 100 years. But the study, published in the journal Global Change Biology, suggests that the connection may not be so simple.
Climate change may affect body size in a variety of ways, they note in their paper. For instance, birds might get bigger as they store more fat to ride out severe weather events, which are expected to be more common under global climate change. Climate change could also alter a region’s plant growth, which may eventually lead to changes in a bird’s diet that affect its size.
LeBuhn, an assistant professor of biology, said she was “completely surprised” to find that the central California birds were growing larger over time. “It’s one of those moments where you ask, ‘what’s happening here?'” The results were so unexpected, she said, that the findings made them take a step back and look more closely at how climate change could influence body size.
The bird data come from two long-term “banding stations” in central California, where a wide variety of birds are captured, banded about the leg with an identification tag, and weighed and measured before being released. Many of the same birds were captured each year, allowing the researchers at the sites to build up a unique database that could be used to track changes among the birds over several decades.
The researchers used data from 14,735 individual birds collected from 1971 to 2010 at the Palomarin Field Station, near the southern end of the Point Reyes National Seashore, by researchers from PRBO Conservation Science. Their study also included data on 18,052 birds collected between 1983 and 2009, from the Coyote Creek Field Station at the southern end of the San Francisco Bay by the San Francisco Bay Bird Observatory.
“At the time I started my research, a few studies had looked at body size changes in a few species in Europe and the Middle East, but no one had examined bird body size changes in North America,” said Goodman, who now teaches Biology and Environmental Science at San Francisco’s Jewish Community High School of the Bay.
“We had the good fortune to find an unexpected result — a gem in research science,” she added. “But we were then left with the puzzle of figuring out what was going on.”
After testing and discarding a number of other explanations, Goodman and her colleagues were confident that climate change was behind the longer wings and bigger bodies in most of the birds. The birds may be responding to climate-related changes in plant growth or increased climate variability in central California, the researchers suggest in the paper.
“The fingerprint of climate change is showing up in many of our ecosystems,” explains Nat Seavy, research director for the Central Coast at PRBO Conservation Science. “The challenge is to use the long-term data we’ve been collecting to understand how, where and why these changes are occurring.”
The findings offer a glimpse at the potent effects of climate change across a wide range of species, LeBuhn said. “Even over a pretty short period of time, we’ve documented changes in important traits like body size, where we don’t expect to see much flexibility.”
“But in some ways,” she added, “it gave me a little more hope that these birds are able to respond — hopefully in time — to changes in climate.”
“Although it is encouraging that species are changing in response to climate change,” said Seavy, “it is also troubling that environmental stressors are pushing and pulling on species in diverse ways…What will happen to our ecosystems as some species get larger and others get smaller? We need long-term monitoring to help us understand the impact of these changes.”
“Avian body size changes and climate change: warming or increasing variability?” appeared online Oct. 12, 2011, published by Global Change Biology. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02538.x/full
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This one is a no-brainer. But they didn’t design a very good study. Bird size has to do with diet, as has been mentioned above. They should have studied insect emmergence as a function of spring temperatures. We had a COLD late spring. By the end of the summer, our grasshoppers were scarce and tiny this year. Not much food for birds and it took longer to gather the same amount. I would guess that insect emmergence is a far better predictor of bird size than any other proxy. And soil warmth resulting in larger seed heads would predict the same thing. We are just coming off of a warmer oscillation. Throughout that period, I would guess that birds got larger because insects were more abundant and bigger. Over the last 6 years, our grasshoppers have gotten progressively smaller and less abundant. Go back a few more years and we are talking grasshoppers everywhere the size of toy planes!
No no you ornithologists don’t understand the science. Climate change causes more umm…err..climate change-
http://www.news.com.au/breaking-news/climate-change-linked-to-extreme-weather/story-e6frfku0-1226183016551
Well with all that snow bringing down your power lines so early in the season, you didn’t think it was all about global warming did you?
Jer0me says:
November 1, 2011 at 1:17 am
The results were so unexpected, she said, that the findings made them take a step back and look more closely at how climate change could influence body size.
It has often been observed that animals respond to environmental changes sooner that humans become aware of the change. The most likely explanation for the increase in bird size is that the birds anticipate that the climate will be getting colder in the future. The near record snowfalls in many areas over the last couple of years suggest the bird know quite a bit more than climate scientists about what is to be expected.
Forgot the money quote-
“But teasing apart the role of natural fluctuations in the weather and rising levels of greenhouse gases in the atmosphere has proven devilishly difficult for scientists.”
Well you know those little Devils???
Rational Debate says:
November 1, 2011 at 3:06 am
Well, yer gonna have to work a skintch harder than that – the shortest people in the world also live in Africa – pigmies.
The Chimbu are a tribe of pigmies in Papua New Guinea. They are commonly employed as night watchmen, because of their skills with a bow and arrow. They sit on the roof of your house and put arrows into anyone that tries to come over your wall. This is not something that happens in remote villages. It is common in cities such as Port Moresby and Lae.
Also in Papua New Guinea are the Buka Islanders, which are a tribe of giants. The men and women are all routinely over 6 feet, with the men approaching 7 feet, yet they are not slender. In color they are purple black with fine features and straight hair. They resemble Persians more than Melanesians.
There cannot be a greater contrast in size and appearance between two peoples living in such close proximity, separated by just a few miles of water. No doubt the differences are due to climate change.
re: ferd berple says: November 1, 2011 at 8:10 am
I’m certain you’re correct, Ferd. The crucial quesiton is, will these populations be able to migrate fast enough to escape doom as the climate change continues? We cannot be optimistic for their futures, as the island topography limits their furthest possible movements with altitude change as a possible temporary escape. This is particularly true for the pygmies, as their legs are so short they cannot migrate as rapidly as may be needed for survival without further drastic morphological changes to their body sizes. 😉
Will major league basketball teams, and top level gymnasts, be forced to migrate as a result of climate change? (sorry, I couldn’t resist!! Wouldn’t you just love to see the paper title appear as peer reviewed somewhere, tho? Just think, it could win an ig-Nobel Prize!! {VBG})
My study shows a direct link between the number of student loans and scholarships vs idiotic grant wasting papers. By stopping scholarships and loans we could save enough grant money to pay down the national debt.
Further study is needed send grant money.
“larger birds cause climate change” has the same correlation as their ‘conclusion’.
This statement <i<“We had the good fortune to find an unexpected result — a gem in research science,” she added. is also interesting. Does she always do ‘research’ thinking that she knows all about the subject of her studies such that she is surprised by an unexpected result?
Isn’t the point of research to find out something not known previously? If so, one should expect unexpected results, not just reinforcement of preconceived ideas.
re: John Trigge says: November 1, 2011 at 4:04 pm
True, but the majority of studies don’t manage to beat the null hypothesis, or at best only add a small increment to what is already known. Null results are probably as valuable as positive results – but they’re not nearly so sexy and so unfortunately don’t often get published. Each, however, is a case of “we suspect xyz about abc, but our hypothesis wasn’t correct.” As such, each informs us what is NOT a good hypothesis regarding abc (assuming a well designed & conducted experiment, of course). That information is hugely valuable in terms of helping us not try re-inventing the wheel – but it’s often lost because journals publish the sexy results, and null results don’t help bring in grant money, enhance reputations, promote careers, etc. So much of the time the researchers don’t even bother writing up the results. It’s a darned shame really, but is also human nature.
I’ve been meaning to thank both JohnWho says: October 31, 2011 at 4:50 pm and Max Hugoson says: October 31, 2011 at 4:52 pm for the play on words – gave me a grin!
re: James Sexton says: October 31, 2011 at 5:21 pm
James, unfortunately I don’t know if it’s still updated or not – but I went ahead and submitted it in case you or others hadn’t already. I included links to this article, the eurekaalert press release (or whatever it’s called!) article, and the wiley listing of the actual article.
The birds body have been shrinking, but their turds are still the same size. This means people will be pooped with dog sized crap when the see a humming bird. This statement is also true if the birds do get bigger in size. Either way, we will need to raise taxes to prevent oversized turds that will damage cars, buildings, and road infrastructure. This will also lead to more use of water to wash the excrement from cars, building and roads. Water is already being overused and will result in more taxes to prevent this. Bigger birds will also breath more raising CO2 levels. You will work for the rest of your lives, but your money will go directly to the government who will provide you with a place you can rest your head after your 80 hour work week.
Okay, REP. Try to exercise a little C.O.N.T.R.O.L. and stop trying to Get Smart with your comments. Otherwise there may be total K.A.O.S.
“”””” Chuck Nolan says:
November 1, 2011 at 3:37 am
George E. Smith; says:
October 31, 2011 at 4:43 pm
——————————————————-
The Huia is one of New Zealand’s best-known extinct birds because of this bill shape and its sheer beauty and special place in Māori culture and oral tradition. The bird was regarded by Māori as tapu (sacred), and the wearing of its skin or feathers was reserved for people of high status.
Looks like the islanders “used” them up. “””””
“”””” the wearing of its skin or feathers was reserved for people of high status. “””””
In the early years of the 20th century, when the Huia went extinct, there weren’t exactly a whole lot of Maori persons of high status. It was sometimes used in making the Korowai, or sacred cloak, which only chiefs wore.
As I recall, I have seen precisely one real traditional Korowai, and that in the Auckland war Memorial Museum.