Scary-smart

Halloween raven

Ravens populate the mythology of many cultures throughout the northern hemisphere  (Photo: John North/iStockphoto, Used with permission).

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[I’ve been frighteningly busy throughout the month of October, so I’m reprinting this post from October 2011 in honor of Halloween, and ravens.]

Fright-night is lurking just around the corner. Frankensteins, mummies, zombies, ghosts, and golems will soon leave their lairs to roam freely through our cities and suburbs, searching for something to eat. Butterfingers, Baby Ruths, and brains—oh my!

poe's ravenReanimated but mindless creatures? HA! They don’t scare me. It’s the ones I’m not so sure I could outsmart that give me nightmares. You know… Hannibal Lecter. Patrick Bateman. Brilliant but mad scientists. Shape-shifters, tricksters, and ravens.

That’s right—it’s Poe’s gently rapping, tap-tap-tapping apparition, the common raven (Corvus corax), that keeps me up at night. Similar in appearance to the American crow (Corvus brachyrhynchos), but larger and more slender with a wedge-shaped tail and a heavy, arched beak—a santoku blade to the crow’s steak knife.

Now, understand that I’m not implying they’re evil. It’s just that there’s definitely something spooky about a massive, inky bird with a genius IQ and an inclination towards… exploiting opportunities, shall we say.  Humans have long considered these birds both charismatic and ominous, fascinating and frightening. Spread across much of the northern hemisphere, ravens have stained the mythologies of native people Valkyries by Emil Doeplerthroughout their range. In Scandinavian cultures, this feathered carrion-eater was associated with war, blood, and corpses and their Valkyries—goddesses who decide which warriors will die in battle and who will be granted an afterlife in Valhalla—often were accompanied by ravens. The Celts made a connection between ravens, war, and death as well; true to their inherent interest in metaphysics, though, they also credited these birds with the ability to see the future, to move freely between worlds and, oddly enough, to play chess (rook is the common name for Corvus frugilegus, a European member of the raven-crow clan).

Mythology aside, ravens have been judged by humans to be among the smartest of all birds. That may be damning them with too-faint praise. Various studies in and out of the lab have tested researchers intelligence and creativity while they attempt to test the raven’s problem-solving skills. The jury’s still out on which party finds these efforts more enlightening. Ravens have been observed applying an understanding of cause-and-effect to the problem of filling an empty stomach—they learn to associate the sound of a rifle being fired during hunting season with the presence of a carcass (similarly loud sounds are ignored). Not content to simply wait for a scavenging opportunity, ravens will work in pairs or even larger teams, using a distraction strategy to separate adult birds and mammals from their vulnerable children, to gang up on prey too large for a single bird to overwhelm, or to defend resources and territory against neighboring gangs. Nature, it has been said, is red in tooth and claw, and ravens are definitely a part of that gruesome heritage.

There’s more to the story, of course—isn’t there always? Ravens are a threat to any number of wild youngsters, but they are devoted parents to their own offspring, who remain dependent for longer than many other bird babies. Both male and female are involved in parenting and are thought to mate for life.

Ravens aren’t as social as crows—they would prefer to go trick-or-treating alone or in pairs than in a mob—but they aren’t loners in the stereotypical serial-killer sense. During winter months they will form a flock, a.k.a. an unkindness (who comes up with these names?!), to find food during daylight hours and stay warm at night.

raven playing with the windOne very appealing characteristic is their sense of fun. Ravens are audacious, acrobatic flyers who take obvious pleasure in practicing dives, rolls, and loops, or even flying upside-down. I’ve personally watched ravens play with the wind blasting up the face of a cliff or a tall building, a sight that never fails to make me long for wings of my own. A favorite game, particularly among young ravens, involves climbing high in the sky holding some object, dropping it, and then racing gravity to catch it midair.

I also learned that here in North America, ravens have been assigned a very different mythological role than in Europe. Pacific Northwest legend has it they take a kind of noblesse oblige attitude toward the human race. Grandfather Raven is portrayed as a devilish philanthrope, a Robin Hood figure who stole the Sun, Moon, Stars, Fire, Water, and even Salmon from various deities and gave them to the people. How would you like to find those treats in your goody bag on Halloween?

Perhaps ravens, like so many scapegoats before them, have been unfairly vilified.  We should never forget that the job of predators and scavengers is thankless, but a crucial component of healthy ecosystems. French author Andre Gide may have said it best, “There are very few monsters who warrant the fear we have of them.” I think it’s time to change my thinking.  From this point forward, I’m going to dream of playful, benevolent ravens and be frightened nevermore.

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© 2011 Next-Door Nature— no reprints without written permission from the author. Thanks to Ian Burt (Poe’s raven) and Ingrid Taylar (raven playing on the wind) for making their photographs available via a Creative Commons license. Walkyrien by Emil Doepler is in the public domain.

Waste management

American black vulture

American black vultures work hard to keep the environment clean  (Photo: Rusty One, CCL)

[This post was originally published on Apr 9, 2011.]

The air wasn’t filled with the thumping of Rubbermaid® recycling bins or the metallic squeal of a dumpster being lifted high above a clumsy automated truck, so the last thing I expected to see when I came around the corner was three members of the neighborhood waste management team standing in the middle of the street.

On their lunch break, no less.

Then again, if you’re an American black vulture (Coragyps atratus), feasting on freshly squished squirrel is one of your duties as a sanitation worker.

Rather than rummaging down streets and alleyways, black vultures take to the skies. Catching a thermal updraft to soar at altitudes that provide sweeping views of the landscape below, they rely more on excellent eyesight than a keen sense of smell to do their job.

It’s all for one and one for all in black vulture communities; when one bird hones in on area in need of garbage collection and begins to descend, the rest of the scrap-heap squadron will be on her tail, ready to pitch in.

black vultureEvery clean-up crew needs a uniform—something that hides stains while providing a little protection from the elements. Baggy-butt coveralls? No, thank you! Feathers provide insulation from both hot and cold weather, and how can you beat basic black for low maintenance and classic sophistication? Add to that a generous cowl neckline that can be pulled up to cover a bare pate, or down when it’s time to dive into a decontamination chore head first, and you’ve got a versatile and hygienic fashion statement.

They might not strike you as endearing creatures, but I have a soft spot for these scavengers. Back when I had wildlife rehabilitation permits and had an active practice, I received a black vulture nestling from the Texas A&M veterinary college. The little fellow reminded me of an old boyfriend—never mind why—so I christened him accordingly and, unbeknownst to my landlord, turned the kitchen of my one-bedroom apartment into a vulture nursery. These birds don’t waste time building nests, preferring to lay and incubate their eggs on bare ground, so my vinyl flooring must have seemed reassuringly familiar to the youngster.

Once he was stabilized, I began to look for a rehabilitator elsewhere in the state who worked with this species. Blacks are more social than turkey vultures (Cathartes aura), our other North American vulture species, so finding some siblings for this fuzzy beige only child was a high priority. Unfortunately—or maybe it’s a good thing—vulture chicks aren’t common patients at wildlife rehabilitation centers. I don’t know if this is because these birds have small families, or because they are cautious parents who raise their young out of the spotlight of human activity, or maybe people are simply less likely to rescue a bird they think of as a harbinger of death.

As a result, it took several months to find a new foster parent. During that intervening time, I learned there’s more to these dumpster-divers than meets the eye. For example, I discovered that vulture chicks investigate everything with an endlessly curious beak. Standing barefoot in front of the open refrigerator door, before long I’d look down and see that wrinkled black head delicately and determinedly shredding the cardboard soft drink carton, or I would feel a tickle and look down to see him attempting to pluck a loose thread from the hem of my pajamas. I would smile, charmed right down to the tip of my big toe, only to notice the chick was trying to exfoliate said toe, one hair at a time.

Eventually, it dawned on me that he was using me and my toe to practice for the day when he would apply that clever, hooked bill and tear open a carcass like an overstuffed Hefty® Cinch SAK, and suddenly a bedtime snack didn’t seem all that appealing. They give you nightmares, you know.

© 2011 Next-Door Nature— no reprints without written permission from the author. Thanks to Gregory Moine and Anita363, who made their photos available for use under a Creative Commons license, allowing us to illustrate the black vulture’s feathered cowl-neck attire. Rusty One’s photographer’s original photo can be seen here.

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Sentry duty

blue jay

Blue jays keep a close watch on their neighborhood (Photo: Rick Leche, CCL).

[This post was first published on Feb 12, 2011.]

JAY!  JAY!  JAY!

Uh oh. I’ve been spotted, and the guards have ratted me out.

HALT! Who goes there?

Thought you could slip past, did you? Not on my watch. Hey everybody—look!

LOOK! OVER THERE!

Steller's jay

Steller’s jay (Photo: Allan D. Wilson, CCL).

Every non-human ear in the neighborhood takes note. It feels a bit like being caught at an awkward moment by the paparazzi. But I don’t take it personally. I know everyone who wanders past is subject to the same protocol—people, cats and dogs, hawks, snakes, you name it. Jays take sentry duty seriously. Any real or imagined threat to the forest citizenry is duly noted and announced.

western scrub jay

Western scrub jay (Photo: Len Blumin, CCL).

Jays are part of a large family. Their Corvidae cousins include gray jays, nutcrackers, crows, ravens, and magpies, as well as some species we’re not that familiar with in North America–choughs, treepies, and jackdaws. In the Americas alone there are over 30 different species christened with some variation of the “jay” brand. The five scrub jays (Aphelocoma spp.) and the pinyon jay (Gymnorhinus cyanocephalus) closely favor one another, but two members of the North American branch have made striking and unique sartorial choices. Once you’ve seen a Steller’s jay (Cyanocitta stelleri) or a blue jay (Cyanocitta cristata), you’ll never mistake them for any other bird.

Florida scrub jay

Florida scrub jay (Photo: B. Walker, CCL).

Of course, they’re not really blue. It’s just a trick of the light called a schemochrome. If you find a blue jay feather you can watch the color disappear and reappear as you roll the shaft between your fingers, changing it’s position relative to the sun. These forest defenders are high-tech.

When they’re not spying on everyone, jays pitch in to give the next generation of trees a head start. Okay, that’s probably an accidental community service. Jays bury acorns and then fail to use them all at snack time. The seeds germinate and—poof!—you’ve got a new oak tree. If society benefits from your actions, intentional or not, shouldn’t you still get some credit?

 

piñon jay

Pinyon jay (Photo: Tony Randell, CCL).

Despite their public service efforts, jays have a reputation as bad birds. Maybe it’s the black mask some of them wear. More likely, it’s the abuse of power so often attributed to their ranks. Eye-witnesses tell of raids on the nests of other birds for eggs and hatchlings, but one extensive study of blue jay feeding behavior found only 1% of these feathered neighbors had evidence of eggs or birds in their stomachs. You’ll also hear stories of jays who trick fellow backyard residents into leaving the feeder by mimicking hawk calls. Now, I can’t deny that some bullying does occur. Think of it as the price of protection, if you must. But judge not, lest ye be judged. Keep in mind that both Steller’s and blue jays have complex social systems and tight family bonds.

Birds, like people, are rarely all good or bad. Your perception of how the scale tips often depends on your point of view. Life isn’t always black and white, or even shades of gray. Sometimes, it’s not even blue.

© 2011 Next-Door Nature— no reprints without written permission from the author.

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 those species who 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 Texas the past year, 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 non-human ears. 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) and 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!

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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)..

Running start

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American Coot Takeoff (Photo: Matthew Paulson, CC license)

Some birds, including the American coot, need a long water runway to get airborne (Photo: Matthew Paulson, Creative Commons license)

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Hard landings. Anyone who’s a frequent flyer has experienced a few. Always disconcerting, occasionally dangerous. My most memorable touchdown was a trip from College Station, Texas, into Albuquerque on an Embraer ERJ-XXX. I forget which number, but it was one of those 3-seats-across models. One by one, passengers ducked through the doorway and tried to return to their full upright position, only to be temporarily twisted by the low ceiling into a fair approximation of Dr. Frankenstein’s personal porter, dragging themselves down the narrow aisle behind carry-ons in an ungainly but oddly synchronous choreography until each Igor found his or her assigned row.

I crammed my gear under the seat in front of me and strapped myself in right above the left-side wheels, although I was unaware of that fact at the time. It was an uneventful flight with no turbulence to speak of and a clear, bright blue sky. We made our approach, descending slowly as we grew closer and closer to the runway… then over the runway… then

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BAM!!

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Well, I guess the pilot got impatient, or maybe the end of the landing strip was coming up faster than expected, but we dropped to the pavement like a bowling ball falling out of the back of an unzipped travel case. I thought the landing gear was going to come up through the floor and imagined the plane careening along the concrete on its belly in a shower of sparks.

Instead, after a long, pregnant pause, the flight attendant simply welcomed us to New Mexico as we taxied to the jetway. But the cabin, previously humming with friendly chatter, went completely silent and stayed that way until the captain turned off the fasten seat belt sign.

Eared grebe glance (Photo: Jack Wolf, CC license)

An eared grebe in winter plumage.

I was reminded of this experience last month, when I heard reports that 3,500 migrating eared grebes (aka black-necked grebe, Podiceps nigricollis) mistook a snowy Walmart parking lot in Cedar City, Utah, for a lake. The grebes came in prepared for a water landing and, as anyone old enough to walk (and to fall) knows, asphalt isn’t as forgiving as H20. For over 1,500 birds it was a fatal error—some died immediately upon impact, others shortly after. For some who lived long enough to be found by wildlife rehabilitators and good Samaritans, euthanasia was the only humane option.

Even the ones who escaped injury needed help. They were found rowing across the landscape using their wings as oars, getting nowhere fast but too aware of their vulnerable position to do nothing but wait for a predator or scavenger to spot a dark bird struggling against a snowy white background.

6 of 6 Pacific Loon in Distress (Photo: Mike Baird, CC license)

The Pacific (Gavia pacifica) and other loons are true water birds, diving and swimming after fish with speed and grace. But out of water they are unable to take flight, and find walking difficult.

There are a large number of bird species associated with water who need a running start across a watery runway to become airborne, even for short flights; they include grebes, loons (Gavia spp.), rails (Rallidae), diving ducks (Aythyinae; aka pochards or scaups), and many sea ducks (Merginae).

The Utah stranding was unusual primarily for the number of birds affected, but similar groundings happen with some regularity during both the spring and fall migration as well as other times of the year. When I was the director of a wildlife rehabilitation center in Houston, every now and again an American coot (Fulica americana) would be ushered through our doors in a cardboard box. A single bird, usually, or at most two or three. In this case, it wasn’t snow that caused the optical illusion but heat. During Texas summers, hot asphalt roads apparently shimmer like water, at least to avian eyes, so a highway looks like the perfect place to stop for a little lunch and a quick dip, not to mention a long, straight liquid launchpad when it’s time to wing away again.

Canceled flights are such a pain in the neck… and other places, too, at times.

Merganser taking flight 2 (Photo: Mark Dalpe, CC license)

Under the right conditions, some species of waterfowl such as this female common merganser (Mergus merganser), can mistake fields and even roads for water.

Surprisingly, most of these water-walkers did survive their fall to earth. Once grounded, however, they had to hitch a ride to our center. There, we would tend to their cuts, scrapes, and bruises and then give them a helping hand back into the sky by dropping them off at an appropriate body of water. A quick look around to get their bearings and they were on their way, pedaling across the water as furiously as the pilot of a Gerhardt cycleplane but with much better results.

The snow that seduced so many birds into a making a pit-stop in Utah may actually have lessened the devastation by providing a bit of slip and slide to cushion the crash. Happily, International Bird Rescue reports that approximately 2,000 grebes were rescued and released the same week—that’s about as good as it gets in these situations, I suppose.  With any luck at all, they’re now enjoying some R&R and a little southern hospitality.  May they have friendly skies and tail winds for their return flight.

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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: Matthew Paulson (American coot); Jack Wolf (eared grebe); Mike Baird (Pacific loon); and Mark Dalpe (common merganser).

Drummer boy

male pileated woodpecker by ucumari

The male pileated woodpecker may not have the most sophisticated sense of rhythm, but he's a stylish drummer nonetheless (Photo: ucumari, Creative Commons license).

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The holiday soundtrack, which retailers now begin to cue up before the Thanksgiving dinner plates have been cleared from the table, has a limited playlist. Even though the variety of artists covering these tunes is diverse, it doesn’t take long for the music to become little more than background noise. However, there’s one tune that always snares my attention—instantly I’m transported back in time to another Christmas… to a crisp, sunny afternoon on a favorite trail at the Houston Arboretum and Nature Center. That day, the sound of a tree-house being constructed high above my head caused me to  glance up, and I caught my first thrilling glimpse of a not-so-little drummer boy.

female pileated by Syd Phillips cc

The female pileated woodpecker doesn't have the red forehead and "mustache" of her male counterpart.

About the size of a crow (16-19 in. or 40-49 cm), the pileated woodpecker (Dryocopus pileatus) is North America’s largest woodpecker (unless ornithologists can prove that ivory-billed woodpeckers (Campephilus principalis) still exist). At first glance, one might reasonably doubt my ability to determine that this was, indeed, a drummer boy. Adult pileated woodpeckers are easy to identify, but unless you look closely they don’t appear to be sexually dimorphic (males and females of the same species differ in appearance). But I was close enough to see the telltale signs of a male bird—a red forehead and “mustache” to go with the pointy scarlet gnome hat sported by both genders.

Since that first lucky holiday outing, I’ve had the good fortune to see many other pileated woodpeckers, but it’s always a bit of a jolt to the system. Perhaps it’s the combination of size and pointed head, or maybe its the wing-beat pattern during flight, but there’s something eerily prehistoric about this bird. Imaging you are ambling down a wooded path, enjoying the great outdoors but allowing your mind to wander where it will… when out of the corner of your eye your subconscious spots a pterodactylus!

It takes only a second or two for your conscious brain to recognize the error, but not fast enough to prevent your adrenal glands from springing into action, bathing your reptilian brain in fight-or-flight chemicals, turning your heart into a percussion instrument.

Human drummers display a assortment of styles—Afro-Cuban, blues, jazz, zydeco—and the same can be said for the avian set. But there’s not a lot of subtlety to a pileated groove. You can break the beat down into two sets—drumming and tapping.  To my ear, the drumming sounds most like an enthusiastic, albeit novice, carpenter: pound furiously for 2-3 seconds, less forcefully as muscles quickly tire… rest for a minute…  bash the next nail for 2-3 seconds… repeat. Tapping, which is slower and metronomic, often serves as a form of mated pair communication.

pileated foraging hole by Naomi Van Tol ccLooking for signs of pileated woodpeckers in your neck of the woods? It helps to live on the eastern side of the continent, although you can find them across much of Canada and down along a fair bit of the western U.S. coast. This species doesn’t migrate, and once a pair has established a breeding territory they defend it year-round (although they’re a little more relaxed about it during the winter months). So, assuming you’re in the right neighborhood, the next step for spotting this hammer-head is to look for squares. I’m not suggesting these rakishly attired birds aren’t hip—just that they have a stereotypic method of excavating the carpenter ants and wood-boring beetle larvae they like to eat. Unlike many other woodpeckers, pileateds don’t waste time drilling a succession of small holes into tree bark. They gouge out large, roughly rectangular chinks instead; a practice that can be quite damaging to small trees, but it’s beneficial to other bird species who come along and feed on left-overs after the bigger bird has flown the coop.

nestling pileateds by Larry McGahey cc

Pileated woodpecker nest cavities usually have more than one entrance.

Pileated pairs share child-rearing duties, and they prefer to use a different nursery for their offspring every year. That means each April the male carves a new nesting hole, leaving last-year’s crib vacant for other cavity-nesting creatures to use for many years to come. Biologists don’t really understand why some species exhibit nest site fidelity while others do not, but in the case of the pileated woodpecker, this philanthropic service improves the overall health of the ecological community.

All drummer boys—and girls—have a knack for gift-giving, it seems.

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© 2011 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: Syd Phillips (female pileated); Naomi Van Tol (pileated foraging sign); and Larry McGahey (nestling pileateds).  Thanks also to Marty Stouffer’s Wild America Sound Effects Library for making the recording of a pileated woodpecker’s call and drumming available through a Creative Commons license.

Yawn

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 much debate. The question is 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.

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 are too exhausted to fly. Can’t fly? Can’t feed. It’s 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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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).

Nutcracker suite

cardinal-grosbeak-crossbill

No, not Tchaikovsky. These are avian nutcrackers (left to right): northern cardinal, rose-breasted grosbeak, and red crossbill. (Photos: ehpien, Conrad Kulper, and Eugene Beckes, Creative Commons licenses)

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Ever wonder why hens’ teeth (and any other kind of avian teeth for that matter) are rare? It’s because teeth are heavy. That’s a problem if you live life on the wing but can’t use a knife and fork to cut your meals up into easy-to-swallow morsels.  A bird’s beak (aka bill) is an adaptation to flight that serves most of the same functions choppers handle in Earth-bound creatures, but without the high metabolic cost of carrying around a set of pearly whites.

Bird Beaks by Shyamal and Jeff Dahl, CC

Figure A. Beak shape and size offers a clue as to what the owner likes to eat.

The beak is a sheath of tough skin on the upper and lower mandibles. Wild birds exploit a wide array of feeding resources and niches, and they are aided in this task by a startling diversity of beak morphology (see Figure A). For example, nectarivores (nectar-eaters), including hummingbirds, usually have long, straw-like beaks that reach deep into flowers. Insectivores (insect-eaters) tend to have narrow, slightly curved beaks that can reach into the small crevices where their prey try to stay out of sight. Piscivores (fish-eaters) have a sharp hook, serrated edges, or both, that help them hold on to their slippery supper. Some of the most distinctive beaks, though, belong to nutcrackers.

The northern cardinal (Cardinalis cardinalis) is a familiar and popular resident of cities and suburbs, possibly because it’s so easy to spot and identify. It’s so popular, in fact, that seven U.S. state legislatures have chosen this species to be their avian poster child.  At  8½—9” (21—23 cm) from jaunty crest to tail tip, it’s a medium-sized songbird with a stereotypic nut- and seed-busting beak—short, stout, and cone-shaped. Cardinal beaks can crush more than seeds, as I can personally attest. From time to time a cardinal would find its way, with the help of a kindly Samaritan, to the Houston wildlife rehabilitation center where I used to work. When this happened, I would stand at the intake desk, teeth clenched, trying to muster enough courage to open the shoebox in my hands.  Now, I like cardinals as much as the next person—I’m from St. Louis, after all, where you can walk down any street in the whole town and know you’ll see someone wearing a shirt adorned with a bright crimson bird perched on a baseball bat. You’d think that would make me an insider of sorts, an honorary member of the family who’s entitled to a few special perks. Hardly. Every time him and her cardinals by Steve Wall ccI’ve held a cardinal in my hand, no matter how gentle the exam or treatment, I was rewarded for my efforts with a throbbing blood blister on my palm, administered by a tiny but furious red vice-grip. Who would have guessed you could feel empathy for a sunflower seed?

The rose-breasted grosbeak (Pheucticus ludovicianus) is slightly smaller (7—7½” or 18—21 cm) with a pale, conical bill reminiscent of the cardinal’s, only more zaftig… a chestnut to the redbird’s hazelnut. Of course, it’s natural for kin to resemble one another, and the RBG is, in fact, one of 17 species known as the “cardinal-grosbeaks.”* Grosbeak—from the French grosbec (gros thick + bec beak) is a bit of a misnomer for this striking black and white bird with a cherry cravat (the females prefer a more sedate, sparrow-like wardrobe). Compared to the schnozzes sported by some members of the Cardinalidae clan, the RBG has a proud but modest snoot. Although not as common as its stop-light colored cousin, human development—and the fire suppression policies that accompany it—have caused forests to sprout where once only grasses grew, allowing the RBG to expand its breeding and migration range westward (although the Rocky Mountains have proven to be a tough nut to crack).  They’ve become a more frequent visitor to backyard bird bistros, where they like to snack on safflower, cracked corn, and black-striped sunflower seed. Insects and fruit are part of their diet as well, but seeds account for the majority of their calorie intake, especially during winter months.

The beak says it all—red crossbills (Loxia curvirostra) are true specialists. At first glance you might think this is a bird in dire need of an orthodontist, but that oddly shaped bill allows them to force open conifer cones and extract the tasty nuts inside. The muscles that allow birds to bite down are stronger than the ones used to open their beaks. But unlike cardinals and grosbeaks, who can clamp down with great force on tough-hulled sunflower seeds (and tender wildlife rehabilitator hands), the crossbill can wedge the slightly opened tips of its bill between the scales of a tightly closed pinecone and then bite down, pushing the scale up to expose the kernel. The red crossbill is extremely dependent on conifer seeds—wildlife biologists refer to animals whose very existence depends on a narrowly-defined habitat or food sources as an obligate species. Most granivores (seed-eaters) start their lives eating protein-rich insects, making a dietary change when they reach adulthood, but crossbills feed on seeds from cradle to grave. Of course, there are risks associated with being a specialist… we’ve all been warned against “putting all your eggs in one basket.” But as long as long red crossbill by eugene beckes ccas you follow the advice of Mark Twain and “watch that basket!” there are benefits as well. For example, red crossbills can raise young any time of the year—even during winter—as long as the cone crop is abundant. I guess some nutty looking adaptations are really quite shrewd.

The Clark’s nutcracker (Nucifraga columbiana) uses the same reliable food resource—conifer nuts—to expand its breeding season. But this member of the Corvidae family (jays and crows) takes the idea even further. It is a hoarder, storing surplus pine, spruce, and hazelnuts. They actually have a special pouch under their tongues to clark's nutcracker by Jamie Chavez cccarry seeds over long distances. A single Clark’s can hide as many as 300,000 pine nuts over the course of a year, and they use this cache crop to feed themselves and their nestlings. Research has shown they have a phenomenal memory and can find most of the seeds they’ve stashed, even months later. Most… but not all; some of the hidden seeds germinate, re-establishing the bird’s favorite trees in areas cleared by fires or logging operations. It’s a sustainable harvest practice, however accidental, and a form of basket-watching that would make Samuel Clemens proud.

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* The grosbeak taxa is a conglomerate of distantly related songbirds known as a polyphyletic (“of many races”) group that we’ll explore in greater detail in future NDN posts.

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© 2011 Next-Door Nature—no reprints without written permission from the author. Thanks to the following photographers for making their work available for use through a Creative Commons license: ehpien (northern cardinal); Conrad Kulper (rose-breasted grosbeak); Eugene Beckes (red crossbill); Steve Wall (male and female cardinals); Trisha Shears (2nd red-breasted grosbeak); Eugene Beckes (2nd red crossbill);and Jamie Chavez (Clark’s nutcracker).  Figure A was made available through WikiMedia by Shyamal and Jeff Dahl.  Bird song mp3s files are in the public domain.