The incredible story of bigger shrinking birds, courtesy of global climate change

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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Michael Palmer

Right. The birds anticipate the more frequent severe weather events that have yet to materialize, because that is how evolution works. Of course, if we lived in harmony with Nature, just like the birds do, then we would just know, too, what climate change will bring, and there would be no more pesky bickering and [snip].

Brad S

But weren’t frogs getting samller just last week?

“We need long-term monitoring to help us understand the impact of these changes”
Translation; “We need more dollars!!”

H.R.

To borrow from Twain, “Wholesale return of conjecture for such a trifling investment of fact.”
As I read the article, due to MMGW, birds will get bigger when they don’t get smalle if they don’t stay the same, but some may get bigger and smaller. And they were surprised by this result!

Julian Flood

In the UK great tits adjust their weight depending on how many predators (mainly sparrowhawks) are around. My guess is that all the fast falcons and hawks in LaLa… sorry, California are being mashed by the windmills and the larger chicks, clumsier and slower flyers when just fledged and thus normally gobbled up, are now growing to adult size.
Or something.
JF
Just use your imagination guys — and get a grip, please.

u.k.(us)

Birds have wings so that they may travel to their preferred climate, mostly following their food sources.
It is called migration.
The birds will be fine, as long as they find enough to eat.

John Phillips

This is all bird-brained. There is no discussion of statistical significance. Maybe its in the detailed paper. But in any case, why jump immediately to climate change as the cause?

Jim Barker

I guess it could be possible that some birds grow larger as they age and with more food and good conditions, living longer equals larger birds. Of course, I am not qualified to make such wild speculation:-)

oldseadog

John Phillips:
Climate Change causes everything.
Potholes in the road, increases in taxation, degredation of roofing tiles, everything.

timg56

I liked the part about how they looked at several potential causes and discarded them …
… leaving “It’s climate change.” as the obvious answer. I also noticed the same thing Michael Plamer did – the amazing ability of birds to anticipate events and start to compensate for them before they arrive. Gives a whole new meaning to the term bird brained.

DJ

All they needed to do was read:
http://green.blogs.nytimes.com/2011/10/16/climate-change-is-shrinking-species-research-suggests/
We all know that climate change makes things hotter, and colder…bigger, and smaller. Climate change also explains conflicting studies and theories.

Bob, Missoula

It has been my impression that almost all global warming studies are either models attempting to prove that yes the earth is heating up and man is responsible or yes the earth is heating up and this is how it will damage, change or eliminate life as we know it.
Wouldn’t it make sense to state clearly and unequivocally that these strategies are not acceptable and prove nothing. So if the above methods aren’t cutting it what kind of study would? The key thought here is what would work, what would convince the majority of skeptics. Has anyone said this is the only style of study that would really prove once and for all that global warming is catastrophic and yes man is responsible. Why wouldn’t it make sense to challenge the best of the best on the other side tell them here are the parameters, show your work and let’s talk.
Bob

DocMartyn

diet is the biggest decider of what size the bird will become.
Different diets favor different gut sizes, a change in the types of crops grown will impose a selection pressure on the species.
With some diets small birds do well and others, larger ones.

In the last 50 years I have gone from 130 pounds to 230 because my “climate’ changed. Why can’t the birds?

Garry

“After testing and discarding a number of other explanations grant applications, Goodman and her colleagues were confident that climate change was AGW grant applications were behind the longer wings and bigger bodies in most of the birds. The birds may be responding to climategrant-related changes in plant AGW grant growth or increased climate variability grant variability in central California, the researchers suggest in the paper.”
“The fingerprint of climate change AGW grants 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 grants we’ve been collecting to understand how, where and why these changes are occurring.”

KnR

Its a reminder that despite everything that has happened the AGW funding bucket is still large and well filled and there are still plenty of people looking to get their snouts in it . There should actual be award for research that makes the silliest link to AGW, as there would be quite a few contenders for this ‘honor’ .

onlyme

I wonder if the changes in the food crops being planted that have taken place in the past 27 to 40 years may have something to do with the noted changes, better grains, more resistant to disease, more nutritious, more abundantly found, could not possibly i guess result in bigger birds, more birds, bigger rats, mice, voles and other prey animals for the carnivorous birds to eat … Nah, it is impossible that could explain this phenomenon even in part.

Nik

There is a Medieval look to the approach that wants everything to be explained via global warming. Like the vapours that were responsible for all ills in the Middle Ages. It is not science, but it is kind of cute. Everyone can join the conversation and be an expert.

J Martin

Julian Flood said ;
“La La… sorry, California”
La La Land. Very good. Excellent in fact.

Rational Debate

I’d love to see a good statistician get ahold of this one – McKitrick maybe? While 14,735 birds sounds like a LOT of birds, once you divide by 39 years over which they were caught, that’s all of 377 birds per year – of many different species. The 18K birds over 29 years is a bit better – maybe.
So, how many birds of each species were caught each year? Can they tell if the bird isn’t fully mature and may not have reached it’s full size yet, both in terms of wingspan and separately weight? If yes, were those not fully mature for both aspects eliminated from the count? If no, were enough of each species caught to be able to statistically overcome the issue of immature birds being counted? Next, how did they account for natural variation in levels of food available for each species? Most animals have a cycle where for some years the species flourishes, then for some years they don’t – all of which has a knock on effect on anything that the species either preys on, or is preyed on by – and vice versa.
So it sure would be interesting to know just how well they actually accounted for various factors such as these – and to have a really good statistician then evaluate the whole thing as broken down by someone who knows those various factors, and see if there was actually enough to provide statistical significance. (I sure wish research papers weren’t paywalled, so it was easy to at least take a quick look at basic scientific methods issues associated with the research. Ah well, so it goes.)

petermue

What a big step in evolution!
Frogs getting smaller, so they can hide better from bigger birds!
Why don’t those $&%#* “scientists” simply say, “We need more $$$ funding!”?

Global warming isn’t causing birds to grow, it’s causing rulers to shrink.
We’re doooomed!!!

old construction worker

Now we have “obese” birds. That does it. We’ll have to shut down all the fast food joint in California.

I just can’t believe the crap that passes as science these days. AGW has polluted a lot of scientists minds. Evolutionary biology was my study at university, specifically phylogenetics. There is NO WAY these guys can know what the selection pressures are. There are thousands of factors, let alone human caused selection pressures. Did the Galapagos 30 year study not have any impact on these scientists? CHANGE HAPPENS!!! Geeze.

Stephen Skinner

“What’s making the birds bigger?”
Standing a lot closer will make them bigger.

I have 52 years of empirical evidence that chilly weather makes my bird small…brrrrr

Me

[SNIP: Site policy requires a valid e-mail address. Please comply. -REP]

David Larsen

That’s why Eskimoes are 7 feet tall and play basketball in the hood and Africans are all 5 feet tall and live in igloos.

George E. Smith;

This important result proves beyond any reasonable doubt that birds evolved from Amphibians, and not from Reptiles, since both frogs and birds, are now known to grow larger or smaller if temperatures rise or perhaps fall. This study is entirely consistent with such a model.

Latitude

whew….what a relief
I always wondered why lemmings were so much bigger than capybaras

Tom_R

That extra half a degree can sure work magical results.

alan

Maybe CO2 is good for birds as well as plants! LOL

George E. Smith;

I watched a program on some PBS station from some University zoology department, that was researching how some kind of rat was slowly migrating to higher elevations as humans slowly encroached on their lower elevation habitats. The scientists concluded that global warming was driving the rats to higher elevations. They claimed that the Temperature had risen 5 deg since the 1950s.
During the program they kept whining about how many species of rats and other such critters had gone extinct down through the years; and they also showed the drawers and drawers of dead rats; hundreds of them that they killed and poked full of wires to stop them rottong and falling apart in the drawers.
Evidently they did not make the connection between their drawers full of hundreds of dead rats, and presumably similar stocks of dead animals in other university drawers, and the fact that some of those dead rats are now extinct.
Evidently zoological student killers are a major threat to the survival of some species of rare animals.
It seems to me that the New Zealand Huia bird, which was noted for the totally different beak designs, for the two sexes, which resulted in totally different diets of the two sexes, likely went extinct in the early 20th century due to ornithologists killing them for samples.
At least in California, our birds are only getting bigger or smaller.

oldseadog says:
October 31, 2011 at 3:00 pm
John Phillips:
Climate Change causes everything.
Potholes in the road, increases in taxation, degredation of roofing tiles, everything.
You forgot to mention the JFK assassination. /sarc

ikh

Have that stopped teaching that correlation is NOT causation!
/ikh

So, the CAGW folks said birds would be smaller and now they say they will be bigger?
Well, this isn’t the first time they’ve attempted to “flip us the bird”, is it?
🙂

I’m sorry that NO ONE seems to have caught this one yet. YET another case of the AWG crowd giving us the BIRD. (Apologies to Big Bird and Daffy Duck, both of whom have MORE sense than all the AWG crowd together.)
[REPLY: Sorry, Max. JohnWho beat you to it by just-that-much (TV reference.) -REP]

Dave Walker

If these are resident birds, then local or regional change should have more impact than Global Climate Change. Can any of you folks with a good connection and know-how pull up a graph of temperature anomalies for some nearby stations from 1971 to now ? How about precip, wind, cloud cover changes, CO2 concentration ?

Max Hugoson says:
October 31, 2011 at 4:52 pm
I’m sorry that NO ONE seems to have caught this one yet. YET another case of the AWG crowd giving us the BIRD. (Apologies to Big Bird and Daffy Duck, both of whom have MORE sense than all the AWG crowd together.)
[REPLY: Sorry, Max. JohnWho beat you to it by just-that-much (TV reference.) -REP]

I’ll type slower next time, Max.
We “birds of a feather” need to stick together, as they say.
🙂

This is just another case for the list…..http://www.numberwatch.co.uk/warmlist.htm
Does anyone know if he still updates this or not?

Philip Bradley

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
Jeez. Someone needs to explain to them how Natural Selection works.
Only past changes in severe weather events can cause birds to get bigger. Not that there is much evidence more severe weather events have been occurring.
I think the reason birds are getting bigger is a more productive biosphere from increased CO2 levels, And climate change has nothing to do with it.

RoHa

Plagues of giant yellow birds with mad staring eyes!
We’re doomed!

What warming? The data from BEST study they posted on the Berkeley web site shows that there has been no warming whatsoever during the twenty-first century, in agreement with satellite temperature measurements. Muller tried to hide that fact from the press but it still came out thanks to Judith Curry, an honest member of their team. The only warming satellites actually do see is a short spurt that started in 1998, in four years raised global temperature by a third of a degree, and then stopped. It was oceanic, not greenhouse in nature, and is responsible for the very warm first decade of our century. It is this warming that is responsible for any and all observations of temperature-dependent behavior such as migration, obesity, etc.by birds or animals. These effects do not go back beyond 1998 because there was no warming from the end of World War II until 1998 when a super El Nino warmed us up. Any observations to the contrary are simply in error.

Well, the trees are obviously not conforming to the models, why should the birds…
http://www.physorg.com/news/2011-10-forests-pace-climate.html

Latitude

Philip Bradley says:
October 31, 2011 at 5:26 pm
I think the reason birds are getting bigger is a more productive biosphere from increased CO2 levels, And climate change has nothing to do with it.
======================
ding ding….we have a winner

RichyRoo

‘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.’ hilarious, they think birds read peer reviewed nonsense?
I suggest that there is likely no real trend, Rational Debate asks some good questions.
But if there is a real change, it might be because food becomes more abundent in a warmer world.

“it is also troubling that environmental stressors are pushing and pulling on species in diverse ways…”
I’ve seen this directly. My roses bloomed this year when the spring rain stopped. The stressors of dry soil and hot sun pushed and pulled on them in diverse ways, causing them to produce seeds in the belief that they would not survive. It’s the end of the world!!!! Even worse, the end of the world happens every year!!!!! Multi-year apocalypse caused by rapid warming!!!!! We’re doomed!!!!

BigWaveDave

Bob, Missoula said:
“It has been my impression that almost all global warming studies are either models attempting to prove that yes the earth is heating up and man is responsible or yes the earth is heating up and this is how it will damage, change or eliminate life as we know it.
Wouldn’t it make sense to state clearly and unequivocally that these strategies are not acceptable and prove nothing. So if the above methods aren’t cutting it what kind of study would? The key thought here is what would work, what would convince the majority of skeptics. Has anyone said this is the only style of study that would really prove once and for all that global warming is catastrophic and yes man is responsible. Why wouldn’t it make sense to challenge the best of the best on the other side tell them here are the parameters, show your work and let’s talk.”
They could start by explaining in physical terms how more atmospheric CO2 would increase temperatures.

doug s

Apparently the scientific method now boils down too, observe something, propose some conjecture, publish results as fact.
Here is my scientific study. As more AGW research money is available, more studies will proposed AGW as the cause of some marginal change in something.
I’m willing to bet my study has more validity that this bird bs.

JamesInAustin

Go ask Alice. With apologies in advance to Charles Lutwidge Dodgson and Grace Slick.
One degree makes you larger
One degree makes you small
The one degree in between
Don’t do anything at all
Go ask Alice
When she is ten feet tall
I read a paper that said Dodgson wrote Alice’s Adventures in Wonderland as a critique of the direction that mathematics was being taken at the time. If so he was born too soon, just think what he could create from this material.