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Oasis

The Nissan Watering Hole (Photo: Ingrid Taylar, used with permission)

American robins and other wild creatures have to get creative if they want to quench a winter thirst (Photo: Ingrid Taylar, Creative Commons license)

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Which season comes to mind when you read these words?

parched

desiccated

shriveled

arid

sere

If you’re a wild thing, the answer may well be winter.

Sure, the heat of summer can make any body feel dry as dust. But wild animals, especially species that can tolerate living near people, usually have an easier time finding some moisture when the mercury rises than when it falls.

In cities and suburbs, April brings more than just spring showers. The return engagement of automatic lawn sprinklers turns every pampered landscaping leaf and each blade of carefully tended turf-grass into a diminutive drink dispenser. Fountains splash and spritz and spray. Swimming pools drop all pretense of modesty and shrug off their winter coats. Hoses report for car-washing and child-cooling duty, turning streets and sidewalks into ephemeral streams. Birdbaths and pet bowls brim with cool, clear water.

Squirrel lapping water from window (Photo: David Grant, CC license)Come January, February, and March, creatures have to get creative and a bit brave to quench their thirst, at least in northern climes. Those of us with easy access to indoor plumbing may not realize it, but for wild animals, dehydration is a bigger threat to winter survival than starvation. Even when the clouds are feeling generous, the precipitation they deliver is often in a more or less rigid—and much less quaffable—form. Personally, I like to think of sleet, snow, and ice as the H2O equivalent of hibernation. Unfortunately, water’s winter vacation means more work for those who depend on it.

And that’s everyone. No exception. Animal, vegetable (no, not mineral)… if you’re alive, you not only need to consume water, you are water—60 to 80% water. Even critters who sleep away the short photo-period months depend on water to stay alive, same as the rest of us. They simply tank up pre-torpor and then use the water tucked away in their extra reserves of body fat.

American goldfinch drinking from an icicle (Photo: JDB Photos, CC license)Active animals need water for basic metabolic functions, including proper digestion. This is especially true for seed-eating birds (a group that tends to hang around all year rather than migrate to places where insects and fruit are still on the menu) because there isn’t much moisture in their meals. In fact, it takes extra water to digest high fiber foods.

What happens to birds and mammals who can’t find a source of unfrozen surface water when they need it? The problem is far greater than simply putting up with a dry mouth until you can stop at a convenience store for a bottle of Aquafina. How long an animal can go without water depends on many factors, including their species, weight, physical condition, and parasite load, as well as the weather. Generally speaking, though, it doesn’t take long for life without liquid to get unpleasant. Lose one or two percent of total body water (TBW) and your dehydration is classified as “mild”; however, anyone who’s experienced it (that would be me) is sure to argue that the resulting headache is anything but. The definition of “moderate” dehydration is five to ten percent of TBW… the situation is getting serious now, as your skin dries out and loses turgor (the ability to snap back into place when pinched) and your eyes begin to sink back into their sockets. Over ten percent TBW loss is “severe” enough that you’re unlikely to recover without medical intervention.

The scenario I’ve just described may sound like an environmental disaster waiting to happen… and in cases of actual drought, such as what’s been going on in much of the U.S. the past several years, the impact is rather grim. Under more normal circumstances, winter water is difficult but not impossible to find, and this scarcity offers an opportunity for nature lovers. Want to make wild lives—and wildlife watching—a little easier? Turn on the spigot.

I mean that literally. Providing water can be as simple as letting your outside faucets drip. You probably already do this to protect your pipes from bursting when The Weather Channel warns of freezing temperatures. Perhaps you can afford to do it once a week, or every other day, regardless of the forecast.

BluebirdBath (Photo: Rob and Jane Kirkland, CC license)

If you’d rather keep the water bill low, and the wild ones a little further from the house, birdbaths are a simple way to offer refreshment. They’re easy to maintain, plus you can add an electric, battery-, or solar-powered heater/de-icer to insure that everyone can wet their whistle on even the coldest days. Hard-core backyard habitat aficionados will drool over the possibility of installing a pond or artificial stream. Whatever floats your boat—you’ll find both ends of the water-feature spectrum, and everything in between, at your local watchable wildlife retailer or gardening center.  I promise you, the sound of water is irresistible music to human and non-human ears alike. New resources will be found and greatly appreciated.

What’s more, water is an effective wildlife attractor all year long. When you offer seed, you get seed-eaters (e.g., cardinals, blue jays, house sparrows, and squirrels), some omnivores (e.g., opossums, raccoons, the occasional deer or black bear)—and probably a lot of hulls and other waste that needs to be raked up and thrown away. Feeder maintenance can be an expensive and time-consuming habit. [Be warned, you may also inadvertently lure in some species who like to feast on the feeder regulars. If you find it disturbing to look up from your morning coffee to see a sharp-shinned hawk scattering goldfinch feathers hither and yon, you may find it helps to think of this as progressing from “having a feeder” to “having a food-web.”] Landscape with native plants and you should be able to coax some fruit and nectar fans to visit as well. Few homeowners are willing to do what’s necessary to invite insectivores to dinner, at least intentionally.

But offer everyone something to drink and suddenly your crib is a coffee house, local pub, and hot new club, all rolled into one. Just add water!

[I'm taking a break from writing new posts as I prepare for yet another migration so I'm recycling a few relevant posts to fill in the gap. This one was originally published last year but the message bears repeating. I expect to have a new NDN installment ready for viewing by mid-February.]

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work—just ask). Thanks to these photographers for making their work available through a Creative Commons license: Ingrid Taylar (thirsty robins); David Grant (thirsty squirrel); JDB Photos (thirsty goldfinch); and Rob & Jane Kirkland (thirsty bluebirds)..

Long winter’s nap

arctic fox by emma j bishop cc

There’s nothing quite as contagious as a yawn* (Photo: Emma J. Bishop, Creative Commons license)

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Grab forty winks. Saw logs. For a species that’s habitually short on shut-eye, we humans sure have come up with myriad ways to talk about it. We also spend a lot of time and money studying sleep, or the lack thereof. Yet, in spite of decades of inquiry, researchers still don’t have a good fix on why we—and just about every other living creature—need to nod off.  We’ve had better luck trying to understand other unconscious states, especially those employed by certain non-human species to deal with hard times.

yawning prairie dog by SearchNetMedia ccWinter poses a critical challenge for animals who stay put rather than migrate to warmer climes. Thermoregulation requires calories, but many foods—especially fruits, nectars, vegetation, and insects—are scarce when the days are short. The ability to reduce one’s energy needs can be a life-saving adaptation. Hibernation does just that—it lowers an animal’s metabolic rate. If all goes well, this period of inactivity, which may last several days, weeks, or even months, depending on the species, will stretch stored energy reserves (aka body fat) long enough for the animal to survive until a greener season. “If” depends on many factors, such as the abundance of autumn food resources, the length and severity of cold days, and even the stability of the den site during repeated freeze-thaw-freeze cycles.

When a critter—let’s use the chipmunk (Tamias spp.) as an example—transitions into a state of hibernation, its body temperature drops to near freezing, breathing becomes so shallow as to be imperceptible, and the heart rate decreases dramatically, from 350 to 4 beats per minute.  Although we tend to think of hibernation as a season-long slumber, chippies and other hibernating rodents do wake up every few weeks to have a snack and take a potty break, even though these periods of activity, called interbout arousals, consume up to 90% of stored body fat. There are some champion nappers in this chisel-toothed group—including the groundhog (aka woodchuck, Marmota monax), who sleeps half its life away, setting the alarm for March when it heads to bed in September.

Other examples of sound sleepers include: insectivores like the European hedgehog (Erinaceus europaeus) and the tenrecs (Microgale spp.); the mountain pygmy possum (Burramys parvus)—the only hibernating marsupial; and the echidna (Tachyglossus spp.), a monotreme.  Biologist recently added the mouse lemur (Microcebus spp.) and the fat-tailed dwarf lemur (Cheirogaleus medius) to the hibernator roster; prior to this discovery, we didn’t have any examples from among the primates. Additionally, since winter temperatures in their native Madagascar may reach 86° F (30° C), it’s become clear that hibernation isn’t strictly associated with cold weather. Nor is it limited to mammals; a bird called the common poorwill (Phalaenoptilus nuttallii) snoozes through at least some of the snowy season.

yawning polar bear by Paul Davidy ccIronically, that most famous of North American sleep icons, the bear (Ursus spp.), is the subject of many a drowsy debate over whether or not they are “true hibernators.” Bears often spend far more time sleeping than the so-called “trues,” so what’s all the fuss about?  Well, this is going to sound like nit-picking, but here goes. First of all, a bear’s heart rate drops, but not quickly enough to suit some scientists. Also, while the number of heartbeats may go as low as 8 per minute, the average is closer to 50 per minute. Moreover, during this time the bear’s body temperature remains pretty close to normal. This is a handy little idiosyncrasy that, should the need arise, allows the animal to wake up fast… and often cranky—a fact Santa (and anyone else) should keep in mind when planning a mid-winter visit to the den.

Taking to one’s bed for months on end could be seen as a rather over-the-top response to a simple cold front. It smacks of swooning characters in English romance novels from the late 1700s. Frankly, it’s not everyone’s cup of tea, and many wild critters take a more measured approach. Torpor is the term commonly used to describe these shorter, less dramatic forms of dormancy, although, technically, hibernation and other types of suspended animation are really subsets of torpidity. Call it what you will, there are examples of “temporary hibernation” in all the Classes of vertebrate animals—mammals, birds, reptiles, amphibians, and fish—and it’s commonplace among the myriad spineless critters as well.

For some of the busiest bodies, torpor is a daily habit. Hummingbirds (Trochilidae), for example, have such a high metabolic rate that they need to ingest a steady stream of non-carbonated sugar water (i.e., nectar) during their waking hours or they’ll become hypoglycemic and too exhausted to fly. Can’t fly? Can’t feed—a vicious circle that will ultimately lead to the bird’s death without some kind of intervention. As you might imagine, this need to constantly refuel creates an enormous problem when night falls and these feathered perpetual motion machines must rest. Without some way to temporarily lower their metabolic rate, hummingbirds would never be able to get out of bed in the morning. Never fear—torpidity to the rescue!

rock dove yawning by Tatiana Bulyonkova ccSwifts (Apodidae), chickadees (Paridae), nightjars (Caprimulgidae), and doves (Columbidae) are just a few of the other avian species who go torpid under various conditions. Generally speaking, these birds are fruit-, nectar-, or insect-eaters, and they tend to be on the small side (less than 80g). The snowy owl (Bubo scandiacus), at 1600-2950g is one exception to this rule, and biologists recently added a second, when it was confirmed that the tawny frogmouth (Podargus strigoides) goes torpid during Australian winters.

Personally, I find these new insights into animal behavior thrilling, because they reassure me that what we know about wild creatures is still a drop in the bucket compared to what we don’t know—there are worlds upon worlds waiting to be discovered on this blue gem of a planet we call home.

yawning turtle by Michael Ransburg ccOf course, cold is not the only hardship wild things would rather sleep through. Periods of drought are just as serious a threat to survival, especially for aquatic and semi-aquatic species. When a lake, pond, or stream goes dry, the inhabitants need to dig in. Literally. Turtles and tortoises (Testudines), crocodiles (Crocodylidae), frogs and toads (Anura), salamanders (Caudata), and some crustaceans will aestivate (also spelled estivate)—a drought-driven form of hibernation. They sink down into the mud before it dries completely, sealing themselves in a mucous capsule until the rains come again. If ever there was a time to be glad you can absorb oxygen in the soil through your skin, this is it, because the air in your boggy bubble won’t last very long.

yawning snowy owl by Pat Gaines ccResearchers are intrigued by these alternate forms of sleep and how they might offer clues for solving a variety of human health concerns. Honestly, I understand their fascination but I don’t know how they stay awake long enough to collect any data. Just writing about dormancy has my eyelid feeling so… heavy. I guess it’s… time for…. me to turn… in.

…..Hit the  [YAWN!]  hay.

……….Catch some…..zzzzzzzzz

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*Pop Quiz:  How many times did you yawn while reading this? ;)

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[FYI: Upcoming changes in employment and residency have caused Next-Door Nature to go into hibernation for a little while. I'll re-publish some past posts while the critters are snoozing to help readers ward off cabin fever, and re-emerge sometime in February (when I hope to get back to a regular posting schedule again). Thanks for your patience!]

There’s nothing quite as invigorating as finding a little Next-Door Nature in your email inbox—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2011 Next-Door Nature—no reprints without written permission from the author. Thanks to these photographers for making their work available through a Creative Commons license: SearchNetMedia (prairie dog); Pau Davidy (polar bear); Tatiana Bulyonkova (rock dove); Michael Ransburg (turtle); and Pat Gaines (snowy owl).

2012 in review

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 33,000 views in 2012. If each view were a film, this blog would power 8 Film Festivals

Click here to see the complete report.

Runner-up

Two male turkeys audition but fail to impress the judge (Photo: Teddy Llovet, Creative Commons license)

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I don’t know what American grade school kids are being taught these days—I left Oakville Elementary a couple of decades ago (okay, fine—several decades ago) and since I haven’t had kids of my own I don’t have access to 21st century homework assignments. But I’ll go out on a limb here and bet that most of them know the bald eagle (Haliaeetus leucocephalus) won the 1782 version of American Idol, and that it did so by edging out celebrity judge Benjamin Franklin’s favorite contestant, the wild turkey (Meleagris gallopavo).

That long-ago contest had little in common with the popular modern day version of reality TV. For one thing, neither bird has great pipes. Citizens were never asked to call or text in their votes. Also, the bald eagle has held on to national fame longer than fellow white-headed winner Taylor Hicks, while the turkey hasn’t exactly proven the voters wrong by, say, winning an Academy Award, Jennifer Hudson-style.

On the other hand, we don’t set aside a day each November (or any month, for that matter) on which the eagle takes center stage.  So in honor of Thanksgiving, I’d like to briefly sing the praises of the runner-up… and not just as the star performer at a holiday dinner.

Shortly after Congress immortalized the eagle on the Great Seal of the United States, Franklin shared his disappointment and misgivings over their choice in a letter to his daughter. Given the sparse pelt on his own pate, one might expect ol’ Ben would view the bald eagle as a kindred spirit, or at least harbor a bit of sympathy. Instead, his criticism was as harsh as any doled out by Simon Cowell, describing our new national symbol as “a Bird of bad moral character” who “does not get his Living honestly,” preferring to sup on rotting fish or, worse yet, stealing fresh seafood from more industrious raptors like the osprey (Pandion haliaetus). What’s more, Ben argued the eagle is cowardly, evidenced by how easily it can be driven away by much smaller birds defending their nests and offspring. Not exactly the role model image our fledgling country hoped to cultivate.

The turkey, according to Franklin, is “in Comparison a much more respectable bird,” a “true original Native of America” and a “Bird of Courage” who “would not hesitate to attack” any invader and defend his home turf.

This description might not square with your expectations after years of holiday stories featuring dim-witted, less than inspiring  Butterballs-to-be but the domestic turkey is but a pale and passive imitation of the real-deal.

Wild tom turkeys (as the males are called) will most definitely defend their breeding territory against potential rivals. Large and heavy, they are unexpectedly agile flyers, aggressive fighters, social, sometimes playful, intelligent, and adaptive.  To my knowledge they’ve never been accused of theft or caught dining on carrion (their omnivorous diet consists primarily of acorns and other nuts, seeds, fruit, buds and leaves, insects and the occasional small reptile or amphibian).

As far as moral character goes… well, you know rock stars. Toms strut their stuff in a flamboyant palette of iridescent red, green, purple, copper, bronze, and gold feathers worthy of Adam Lambert. No piercings or tattoos, but oozing cool with a Beat-worthy statement beard of stiff bristles starting just above the wishbone, wattles (flesh hanging from the head and/or neck), caruncles (fleshy growths on the head), snoods (long fleshy object draped across a tom’s beak), spurs and other body art. Their ladies, in keeping with general avian fashion trends, tend to be more conservatively dressed but they can strut like a runway model  when warranted, complete with long legs and outlandish makeup. Out of the spotlight, turkey hens are attentive mothers to their precocial offspring, in contrast to the menfolk, who are polygamous absentee fathers.

(Male bald eagles, it must be said, are actively involved in their children’s upbringing; given his own reputation, Ben might have been well served to heed the old saying about people who live in glass houses before he cast the first stone.)

Like the bald eagle, wild turkeys experienced a perilous decline in their numbers during in the last century, due to overhunting and habitat loss (rather than DDT exposure, as was the case for so many of our birds of prey).  Game agencies took action to protect the species and have been successful in helping the population rebound. So much so, in fact, that turkeys have not only returned to rural fields, pastures, and woodlands but have begun to tour in many major metropolitan areas as well.  In some parts of the country spotting a flock of wild turkeys foraging near a highway, hanging out downtown, or feasting at a backyard bird feeder is no longer a novelty.

That means a growing number of Americans now have a ticket to see  this national treasure up close and personal more than once a year, and at venues other than a serving platter.

For that, I am thankful.

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Start your day with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask first.). Thanks to these photographers for making their work available through a Creative Commons license: Teddy Llovet (cover); keeva999 (turkey in flight); Mic Stolz (plumage); Peter Patau (men).

Brewhaha

red-bellied newt (Photo: janetcetera, Creative Commons license)

Red means STOP… at an intersection or on an amphibian. The red-bellied newt secretes a deadly neurotoxin (Photo: Janetcetera, Creative Commons license).

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Double, double, toil and trouble; 
Fire burn, and cauldron bubble. 
Fillet of a fenny snake, 
In the caldron boil and bake,
Eye of newt, and toe of frog,
Wool of bat, and tongue of dog,
Adder’s fork, and blind-worm’s sting,
Lizard’s leg, and owlet’s wing…
 

During late October, Shakespeare’s recipe for chaos and conflict comes to mind with the sudden appearance on our very doorsteps of all manner of terrifying witches, ghosts and goblins… and political advertising.

The former can be bought off easily enough with bite-sized Butterfingers (a sticky booby trap that guarantees revenge for the extortion in the form of future dental bills).  The latter are a bigger headache, far more demanding, and incredibly persistent. It takes more than a simple head of garlic and the promise of your vote to repel the legions of wannabe legislators. What American needs now, more than ever before, is a magical charm … a powerful protective talisman to ward off bleary-eyed baby-kissing, hand-shaking, promise-making shape-shifters.

rough-skinned newt (Photo-:Judy-and-Ed, Creative Commons license)We need newts.

The amphibian kind; NOT the mammal and former Senator from Georgia.

“Powerful” is probably not the first word that comes to mind when you spy a newt in any of its four developmental stages. Each egg, attached to an aquatic plant during the main breeding season of June and July, is actually quite vulnerable, even when the female makes an effort to fold it inside a leaf. Nor is the larval tadpole menacing when it emerges about three weeks later. That is, unless you are algae, a small invertebrate, or a sibling (fratricide is an all too common practice in this sweet old eat-and-be-eaten world of ours).

newt tadpole (Photo: Mark Kilner, Creative Commons license)Over the next several months, however, a metamorphosis as extreme as any werewolf’s takes place. Where once only a big-eyed head and tail existed, legs buds sprout and lengthen. Feathery external gills are absorbed, replaced by internal lungs. Fully formed efts, as they are now called, will then drag themselves on stubby legs out of the natal pool and venture onto dry land … but the scene doesn’t evoke Creature from the Black Lagoon panic.  At two to six inches in length, adult newts are easy to overlook, generally more slender than their salamander cousins, and not physically threatening in the least.

It’s during the larval transformation that some species also develop a bright, cautionary coloration that hints at their ingenious and formidable defense strategy:  toxic slime.

california newt (Photo: Ben Amstutz, Creative Commons license)All amphibians carry potentially harmful bacteria, such as salmonella. The California (Taricha torosa), rough-skinned (T. granulosa), and the red-bellied (T. rivularis)—known collectively as the Pacific newts*—aren’t satisfied settling a score by giving their adversaries some stomach cramps and the runs, though. They practice biological warfare, secreting tetrodotoxin (TTX), one of the most potent neurotoxins known to science.  TTX, which gets it’s name from the pufferfish (Tetraodontidae) that also carries this poison, is deadly when ingested or when it comes into contact with mucous membranes or breaks in the skin. Within as little as 20 minutes after consuming the toxin the victim will experience respiratory paralysis, and there is no antidote.

Perilous times call for strong medicine but just to be clear, I’m NOT suggesting that poisonous amphibians should be used to rid the world of legislators. Only that in our effort to demand more from elected officials than the ability to raise money and speak in soundbites, we might gain inspiration from a small, seemingly insignificant creature with hidden powers disproportionate to its size.

A newt, perhaps.

Or a voter (not to belabor the point).

But maybe we should heed the lesson of Macbeth’s witches, who certainly knew a thing or two about politics and ambition, and take precautions to insure that newt-power is used exclusively for good and never for evil. After all, Order Caudata, with their ability to regenerate limbs and tail, as well as eyes, hearts, intestines, jaws, and spinal cord, are the envy of many a zombie… and any politician who wants to transform (temporarily) into a more centrist candidate following a contentious primary season.

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There’s nothing quite like finding a little Next-Door Nature in your email inbox—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [starting from the top]: Janetcetera (red-bellied newt); Judy-and-Ed (rough-skinned newt); Mark Kilner (newt tadpole); and Ben Amstutz (California newt).

Finally! (and I didn’t even have to learn Swedish!)

If you’d like to know more about what’s ahead in collision prevention technology—potentially a real life-saver for both human and non-human animals—navigate on over to the Car Talk website and check out my guest blog post.

Next-Door Nature, wildlife crossing sign, Canada

Busy travel corridors call for advanced technology (Photo: Antony Stanley, Creative Commons license)

Size matters

Next-Door Nature, toucan, song sparrow, beak size

When you’re trying to stay cool without air conditioning, it helps to carry a radiator on your face, large or small (Photos: Ame Otoko and Cephas, Creative Commons license).

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A scientists’ work is never done.

That’s because there’s always another layer to peel away, another stone to turn, another angle from which to view the situation.  Case in point—nearly 200 years ago, Charles Darwin made the connection between the size and shape of a finch’s beak and the availability of the seeds they eat; to this very day, no one has been able to produce evidence that undermines his observation and the conclusions he drew from them.

But what if there’s more to a beak than meets the eye?

That’s the question raised by Russell Greenberg of the Smithsonian Conservation Biology Institute. His theory—that beak size may also be an adaptation to temperature regulation and water conservation—has been bolstered by data from two recently published studies.  [Data collected, in part, by a newly minted PhD named Ray Danner. Ray just happens to be a member of my own adopted extended family, and if that name sounds vaguely familiar… well, regular NDN readers may remember that not too long ago I was bragging about another member of this ornithological power couple, Ray’s wife, Dr. Julie Danner.]

black-tailed jackrabbitSome years back, Greenberg noticed a difference in size between the beaks of sparrows living in salt marshes and those of sparrows settled just a kilometer or two further inland. Then a paper published in 2009 reported toco toucans (Ramphastos toco) may lose as much as 60% of their body heat through their long bills, based on thermal imaging and similar to the role played by the large ears of both elephants (Elephantidae) and jackrabbits (Lepus spp.). While many ecologists assumed toucans were a special case, Greenberg wondered—might other birds have evolved larger or smaller beaks to discharge or conserve heat as well?

He chose to test his hypothesis by applying thermal imaging to a subject with a much less prominent proboscis—the song sparrow (Melospiza melodia).  Native to North America, everything about these feathered minstrels is miniature compared to their South American kin. The toucan weighs in at 1-2 pounds (the large bill doesn’t actually tip the scale as much as you might think since it’s mostly hollow) while at 0.4—1.9 ounces the song sparrow is definitely a featherweight.

In the first study, two subspecies were examined. On average, the beak of an Atlantic song sparrow was found to have 17% more surface area than that of the eastern song sparrow, although both birds have similarly sized bodies. Based on the Greenberg team’s calculations, the Atlantic sparrow loses 33% more heat than it’s inland neighbor. The finding suggests beaks may play a role in thermoregulation for a wide variety of bird species.

The ability to stay cool when the ambient temperature rises is critical to survival, but how one gets rid of the excess heat is just as important.  Birds don’t sweat—they pant… and lose not just heat but water in the process. This summer, residents across the U.S. have been reminded just what a precious resource water can be, and never more so than for all the creatures without easy access to a faucet.  Greenberg and his colleagues suggest that a bird’s beak can function like a radiator, releasing heat without losing water. The Atlantic sparrow’s larger bill saves the bird about 8% more water than the smaller beaked eastern sparrow. That may not sound like much but during a hot, dry summer it could be a significant survival advantage.

The second study examined museum specimens of song sparrows collected on the other side of the continent, along the California coast. Sure enough, as maximum temperatures increase, so did beak size… with one caveat.  When the maximum temperature was higher than 98°F (37°C) beaks got smaller… just as was predicted by the original hypothesis. You see, if you took a song sparrow’s temperature the thermometer would read about 105°F (41°C). When the air temperature exceeds the bird’s own temperature, as it does in some regions, a larger beak could actually begin to absorb heat.

While the Smithsonian group has demonstrated a connection between climate and beak size, there’s still plenty of work to be done. For the new hypothesis to garner support, scientists need to see data that ties survival of wild birds to beak size-related heat dissipation.

Meanwhile, the fact that diet influences beak size and shape hasn’t changed—Darwin can continue to rest in peace. But as so often is the case, the more we discover the more we realize just how rich and complex this world and its inhabitants are … even an Earthling as seemingly plain and simple as a sparrow.

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There’s nothing quite like finding a little Next-Door Nature in your email inbox—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [from the top] Ame Otoko (toco toucan); Cephas (song sparrow); James Marvin Phelps (black-tailed jackrabbit); Mr. T in DC (house sparrow on drinking fountain); David Craig (song sparrow in hand).

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