Helicopter Parent

As the most literal of helicopter parents, a ruby-throated hummingbird mom (RTH, Archilochus colubris) takes hovering to a whole new competitive level.

In the case of this feathered sprite (2.8 – 3.5″ long, including bill, and just over 1/10 of an ounce), though, the word “hover” has more to do with the ability to fly than with over-protective child rearing. Which is not to suggest that an RTH mom is neglectful. Far from it… she’s just a bit Type A.

Both male and female RTHs winter in Central America or along the southern tip of Florida, but from the moment a gal returns to her summer stomping grounds in the eastern half of the US or southern Canada, she’s all go-go-go… because her biological clock is ticking like a stopwatch.

Barely hesitating to catch her breath, the first order of business is to find a baby daddy. She’s not looking for ever-after; Mr. Right-for-Now will do as long as he’s strong and handsome. Since the males of her clan aren’t the slightest bit interested in becoming a Mr. Mom this arrangement suits everyone just fine. With barely a look backward by either party following their four-second assignation, he jets off to find another hookup, and she speeds away to shop for flower-down to line the bassinet.

It takes about six days for this mom-to-be to fashion a nest barely wide enough to hold a bottle cap, and tether it to a foundation with strands of spider silk. RTH nests are most often built on a tree branch but unusual alternatives, including loops of chain or extension cord, have proven acceptable in a pinch. Darting back and forth, the female will weave bud scales, lichen, hair or fur, and other creatively repurposed found objects into a cup-shaped cradle. Next, she’ll adorn the nest with lichen and moss, finally lining the interior with a soft, insulating layer.

Once the nursery has been prepared and decorated, 1-3 eggs the size of your pinkie fingernail will appear, and then… a pregnant pause.

Think about it. The longest stretch this single mother ever sits down, during her entire life, is to incubate a clutch of future hummers. Imagine, if you will, the kind of patience, willpower, and elevated estrogen levels it takes for a creature who has lived on the wing, perpetually flitting hither and yon since leaving her own natal nest, to STOP…  settle in… and then just…

……………………sit…

…………………………..for 12-14…..

……………………………………………..long…..

………………………………………………………….idle…..

……………………………………………………………………..days.

During this time, the newly stationary creature will leave her nest only for brief breaks to stretch or grab a bite to eat. She’ll anchor there, day and night, rain or shine. No baby shower, no friends stopping by to say hello; they’re all brooding their own nest eggs. No television, even though this would be a great time to binge watch David Attenborough’s The Life of Birds. No smartphone at the ready to check email, take selfies, and whine to everyone on Facebook that she is bored beyond reason.

Heck, when I manage to stop and meditate for ten minutes two days in a row I feel like a Zen Master.

Once the chicks hatch it’s back to her normal hyperactive life… and then some. RTH nestlings are naked and wobbly-headed, with an appetite that dwarfs their bitty bodies. For the next few weeks, Mom will need to make 1-3 grocery runs per hour,  from dawn to dusk, regurgitating the food she’s foraged and hauled home in her belly into the beseeching beak of each precious child.

Once the babes fledge at 18-22 days old they’ll disperse among the branches… not too far away from the nest or each other initially, but spaced out enough to make dinner deliveries much less efficient for their harried mother. As the kids grow stronger and bolder, they’ll spread out further, testing their own wings… and Mom’s ability to be everywhere all at once.

Oh, and somewhere in that frantic schedule, this solo parent also needs to down enough calories to keep her own metabolism running on all cylinders.

Luckily, she flies like a super-charged, hyper fuel-efficient, über-nimble helicopter. Hummingbirds have been known to reach speeds of nearly 35 mph (55 kph), which is certainly impressive. Not record-breaking among the avian set, though. The difference is that most of the planet’s fastest feathered fliers reach their top speeds in a dive, asking gravity to add a significant boost to their velocity. Acrobatic RTHs can fly straight and fast, too, but it’s their ability to achieve what those avian missiles can’t—a true hover—that sets them apart.

This isn’t using a thermal to save energy, like vultures, ravens, petrels, and other long-winged birds do. That’s soaring. Hummingbirds move their wings in a figure-eight pattern at over 50 beats per second, allowing them to stop on a dime or adjust their position up, down, forward, or backward. That frenetic rhythm is also creates the humming noise that’s the source of their common name.

It also helps that the lady’s jet fuel of choice is syrup. Flower nectar, to be more precise, accounts for approximately 90% of an adult hummingbird’s daily caloric intake. RTHs and other hummers have a large surface-area:body-mass ratio, which means they lose a lot of heat in the normal course of living. Plus, their metabolism is so high they have to enter a torpor once a day, between sunset and sunrise, just to make it through the night without having to recharge.

Unlike the sugar-water mixtures backyard bird enthusiasts cook up to fill hanging feeders, blossom juice consists of more than just sucrose (from which plain white table sugar is derived). Flowers also produce fructose and glucose, as well as amino acids, antioxidants, calcium and other trace minerals, lipids, phosphates, and some protein. Other sources of protein include insects that have found their way inside the flower’s throat, where they are slurped up along with the nectar. Hummingbirds will also glean aphids from plants, pluck spiders from their webs, and nab flying insects mid-air. During breeding season, female RTHs spend a lot of time catching insects because nestlings need a high protein diet to grow and develop properly. Once they mature they’ll gradually switch to the high-carb diet of an adult.

As befits a fast-paced life, in barely the blink of an eye (or the wing-beat of a hummingbird) summer is over. Male RTHs often head south first, in early August. Females tend to delay departure until late August or sometime in September. After months of feeding others—our feathered Supermom may have raised as many as three broods in a single season—the time has come to focus on self-care, and on building enough fat reserves to power through an 18-22 hour non-stop flight across the Gulf of Mexico.

The last of her children have left the nest and are, hopefully, ready for their first migration. RTHs are solitary migrators so Mom’s helicopter parenting days are over… until next year.

Because a mother’s work is never really done.


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© 2019 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 (from top to bottom): Dan Pancamo, Steve Rider, TCDavis, BudOhio, ssemone, BudOhio, and Henry T. McLin.

Bull Session

I say potato, you like potahtos. You wear pajamas, I wear PJs. And a rose by any other name, we’re told, would smell equally sweet. So does it really matter that we all agree on what to call an American bullfrog? 

“HELL, YEAH!” 

That’s the collective cry of taxonomists around the globe raising their voices in indignant protest. (Yes, these are men and women of strong, science-based convictions.) You see, to a biologist who studies the classification of organisms, names are not at all trivial… but they should all be binomial.

Swedish botanist Carl Linnaeus is credited with introducing this ubiquitous classification system, based on bestowing a unique two-word Latin name upon each species, precisely to avoid the kind of misunderstandings that arise when you say ersters and I say oysters.

Or, for example, when one scientist is talking about a fish using one of its common names, “dolphin” (Coryphaena hippurus, aka mahi-mahi, dorado, pompano), and another scientist hears “dolphin” and thinks of a perpetually-smiling bottlenose marine mammal (Tursiops truncatus).

And yet, despite Carl’s best efforts, disagreements persist. As in the case of the American bullfrog, whose official Latin name (Rana catesbeiana or Lithobates catesbeianus, depending on whom you ask) is more likely to be disputed and cause confusion, ironically, than its common name.

The quibble over nomenclature began about 10 years ago and quickly became a quarrel. Darrel Frost, Herpetology Curator at the American Museum of Natural History, suggested a conceptual leap that would divide members of the genus Rana, which includes bullfrogs, into nearly a dozen new genera. Many of Frost’s colleagues, unconvinced that his argument held water, refused to jump into the newly proposed systematics pond.

In response, feelings, opinions, and counter-claims have been aired publicly in peer-reviewed journals. Several years ago, a group of international researchers created a consortium to promote their own preferred adaptation of the froggy family tree. The taxonomy community still hasn’t managed to harmonize this chorus, which is why she says Rana and he says Lithobates.

But hold on… let’s not call the whole thing off just yet.Because, of course, a bullfrog doesn’t need a taxonomist to know exactly who he or she is… once s/he reaches a certain age, anyway.

Sure, there may be some gender ambiguity early on but that’s common among young amphibians. Their sex is determined genetically, although research suggests that for many frog species, exposure to environmental estrogen or variations in water temperature during tadpole-hood can induce male-to-female or female-to-male transitions. Self awareness doesn’t always come easily, and it can take some time for those gender identity questions to work themselves out. Bullfrog development is relatively slow—one to three years from egg to adult, and another two years to reach sexual maturity.

By the time they’re ready to procreate, however, males and females have definite, discernible physical differences. Males are smaller than females, their tympana (external eardrums) are larger than their eyes, and when in breeding condition their throats are yellow; female tympana are equal or smaller in size than their eyes, and their throats are white. There are behavioral distinctions as well—male bullfrogs are territorial over the summer mating season, and quite vocal about it, too; females are relatively silent, although older gals have been known to sing along with the guys. (I have a sneaking suspicion their favorite tune is If I Were A Boy.)

Ok, ok… life, in all it forms, is full of uncertainty and differences of opinion, at the laboratory bench and the water’s edge. But can we all come together on this much, at least? That the creatures featured throughout this post are:

a. Amphibians

b. Bullfrogs

c. Cool.

Everything else is neether/nyther here nor there.


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© 2018 Next-Door Nature. Reprints welcomed with written permission from the author. Thanks to the following photographers who made their work available through the Creative Commons license: Mark Beckemeyer, LadyDragonflyCC, Greg Schechter, Rick Cameron, and Kaibab National Forest.

Telephone

This university town is always less crowded during the summer. Most students are at home or on summer internships, faculty and graduate students are using the break to slip away for some R&R or doing research at field sites, and there are no home football games to bring in alumni and supporters of the opposing team.  While I enjoy the school year, and recognize how much Blacksburg depends on the university and related personnel, I do my best to pause and catch my breath from mid-May to mid-August.

That includes plenty of walks with my wire fox terrier, Dash, along a leafy section of the Huckleberry Trail, a former railroad easement. Tt’s rare for Dash and I to have the Huckleberry trail all to ourselves, at least not for very long. Usually we share with cyclists, runners, and other dog-walkers.

But one mid-July day was an exception. I guess we must have left a bit later than usual, but regardless of the reason, the trail and surrounding suburban backyards were quiet enough for me to hear a feathered fellow shouting his heart out from the power lines above.

I peered skyward and saw the black, white, and terra cotta of an Eastern towhee (Pipilo erythrophthalmus)). I’ve read descriptions of this bird’s call as “Drink your tea!” but to my ears it sounds like, “Drink your tea-hehehehe!”

I stood still for as long as Dash could stand it, enjoying the sight and sound of a serious sparrow with a major case of the giggles. Then we picked up the pace and continued walking.

 

 

Several minutes later… more giggling. Were we being followed? Most likely is was a different individual; it was breeding season, after all, and males tend not to stray far from home base and the Mrs.

 

 

 

 

Further down the trail… more tea, more giggles. I felt like I was hearing a musical baton passed from one bird to the next in an auditory relay…

 

 

 

 

Drink your tea-hehehehe!…

 

 

 

 

 

Drink your tea-hehehehe!…

 

 

 

 

 

Drink your tea-hehehehe!

 

 

 

 

I can recognize a game of Telephone when I hear it! In this case, though, all of the players were excellent listeners who repeated the phrase exactly, with perfect fidelity and zero degradation. Since garbled messages are the whole point and fun of Telephone, I wasn’t sure why all these towhees were laughing.

I’ve heard recorded birds calls I couldn’t distinguish by ear but the sonograms (graphical representations of sound) showed clear variations my hearing wasn’t sensitive enough to notice. Maybe if I had Towhee ears I’d be in on the joke.

When Dash and I returned home I had the strangest craving for a cup of tea (strange because I don’t even like tea).


Who’s playing telephone in your neighborhood?  Share your experiences and comments below! And if you’d like a little Next-Door Nature delivered right to your inbox, click the “subscribe” link in the upper right-hand corner of this page to receive notifications for new posts!

[© 2018 Next-Door Nature, Sidewalk Zendo. Reprints welcomed with written permission from the authorThanks to the following photographers for making their work available through the Creative Commons license: Pat Gaines, Alberto_VO5, devra, Mike’s Birds, Amanda, Ken Schneider, marneejill, and Keith Carver.]

Fast Food

When humans talk about making a breakfast, lunch, or dinner run, it’s understood that we’re speaking metaphorically. Truth be told, we’ll probably drive, not jog, to a local café, convenience store, or Kroger. The same cannot be said about the way greater roadrunners (Geococcyx californianus) grab a meal. Fast food is how these long-legged, long-tailed, long-necked North American cuckoos roll—make that sprint—through life.

I mean that quite literally. Roadrunners are feeble fliers but they can definitely beat feet. Angling the body forward to nearly parallel with the ground as they pick up speed, the tail is held flat, acting as a stabilizer during turns. Their unmistakable X-shaped feet, with two toes pointing forward and two toes pointing backwards, are better suited to life on the run than the typical three-one toe formation of perching bird species. And who needs powerful wings when you can leap skyward, as if propelled by a pogo stick, to grab a snack out of thin air?

If you grew up in the U.S. during the latter half of the 20th century, as I did, you may have some serious misconceptions about this fleet-footed bird, not to mention coyotes (Canis latrans). For example, roadrunners are quick but at top speeds of 43 mph, coyotes are more than twice as fast. Smarter, too.

Moreover, I think Warner Brothers animator Chuck Jones must have grabbed the wrong field guide when he started to sketch, because his roadrunner looks more like an ostrich (Struthio camelus) to me than the iconic avian of the American Southwest. I think you’ll agree that a side-by-side line-up provides plenty of evidence to back up that statement.

Roadrunners do have at least one thing in common with ostriches—both birds prefer more arid, savannah-like landscapes to damp, dense forests. That said, greater roadrunners have been expanding their range, moving east from southern California, Arizona, New Mexico, and Texas, into the juniper, pine, and hardwood stands of Oklahoma, Missouri, Arkansas, and even Louisiana. And while they won’t tolerate densely populated urban areas they are showing up in more open suburban developments.

Like so many desert species, roadrunners have evolved to survive in a low rainfall environment. This includes a gland near each eye that secretes a highly concentrated salt solution, reducing the amount of water lost through their urinary tract. The ability to efficiently use the moisture present in their food reduces the roadrunners’ dependence on scarce surface water supplies.

I have a few more bones to pick with Warner Brothers’ depiction of the life and times of coyotes and roadrunners. For one thing, those cartoon characters would have you believe one is a predator, the other prey. Well, my friends, that’s as wrong-headed as expecting a tiny Acme parasol to protect you from a falling boulder.

The real skinny is that roadrunners are predators, too. Their moveable feast includes just about anything they can catch, including insects, spiders, scorpions, frogs, toads, songbirds, bats, rodents, and lizards. They’ll even pair up to take on a rattlesnake—one bird distracting the serpent, the other sneaking up from behind to pin the head down, rending those venom-delivering fangs moot.

This chick is all business. I’m not kidding.

Once their prey has been dispatched, roadrunners swallow their food whole, so there’s no need to carry around silverware, a la Wile E. Before that hummingbird goes down the hatch, though, there’s an important food prep step that has to take place. Fair warning—the process will make you reconsider the sincerity of that two-dimensional speedster’s goofy grin. I’ll let my friend, fellow wildlife enthusiast, and long-time Albuquerque resident, Janelle Harden, deliver the play-by-play:

“Not everyone would appreciate this, but I know you will! I saw a roadrunner catch a house finch on my driveway the other day. Holding the dead bird by the head, the roadrunner proceeded to bash and thrash the carcass against the concrete curb. Once the skeleton was pulverized and the body limp as an al dente noodle, the roadrunner threw her head in the air, along with the finch, opened her bill, and let gravity do its thing. It was fascinating! Took about 6-8 big swallows, and I swear her eyes got bigger with every gulp!”

I have to admit, I do appreciate Janelle’s field observations, and her description of the roadrunner’s bulging eyes does sounds pretty cartoonish. It’s the kind of thing I could imagine happening to a certain famously incompetent but persistent wild canid. Maybe Chuck Jones wasn’t a total Looney Tunes after all.

Gotta run—that’s all, folks!

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© 2018 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: Anita Ritenour, Photo KentTeddy Llovet, Alan Harper, LDELD, Jo Zimny, and Nick Chill.

Vert-de-Gris

Cope’s gray treefrog on a pepper plant. Photo: Alan Howell © 2017, Star Path Images, Used with Permission.

It isn’t easy being green. Kermit the Frog said it, so you know it has to be true.

He’s always seemed a reluctant celebrity, so my guess is that being the most famous Muppet-amphibian on the planet isn’t always a picnic. I wonder whether life would be a little less stressful if, like some of his cousins, Kermit could change from green to another color when he’d rather not be so conspicuous.

North American gray treefrogs know how to be seen and when to blend into their surrounding, shifting the spectrum from bright emerald to peridot, to gold, copper, platinum, silver, and even gunmetal. Since the places they hang out — trees and shrubs in woodlands, meadows, prairies, swamps, suburbs, and cities — tend toward palettes awash with green and gray hues, these arboreal amphibians can keep their sartorial choices simple. 

What looks like a costume change is actually a rather high-tech, cellular-level special effect created by chromatophores. These pigment-containing and light-reflecting cells, or groups of cells, are present in the skin of certain frogs, as well as some reptiles (including chameleons), cephalopods (such as octopi), fish, and crustaceans. Mammals and birds, on the other hand, have melanocytes, a different class of cells for coloration.

Chromatophores are classified based on their hue under white light:

  • melanophores (black/brown)
  • cyanophores (blue)
  • erythrophores (red)
  • xanthophores (yellow)
  • leucophores (white)
  • iridophores (reflective or iridescent)

The process, known as physiological color change, can be controlled by hormones, neurons, or both. Most studies have focused primarily on melanophores because they are the darkest and, therefore, the most visible. When pigment inside the chromatophores disperses throughout cell the skin appears to darken; when pigment aggregates in cells the skin appears to lighten. Either way, you’ve got an amazing makeover, or a convincing disguise, in no time flat! 

There’s even more to the gray treefrog’s ability to assume an alter-ego than meets the eye —what appears to be a single species is actually two very close relatives: Hyla versicolor, aka Eastern, although there’s a long list of pseudonyms from which to choose (there are more ways to hide than blending into the substrate); and Hyla chrysoscelis, aka Cope’s (which also has a couple of nicknames but not as many as H. versicolor).

Cope’s and Eastern are equally skilled at clinging to and climbing slick surfaces using large toe pads that secrete mucous, creating surface tension. It’s not uncommon to find one plastered against a window pane (allowing for an interesting view of their nether-regions). Both species prefer a diet of small insects, spiders, and snails. Both hibernate under leaves, bark, or rocks. Well, “hibernate” sounds a lot more cozy than the reality… which is that their bodies pretty much freeze and their lungs, heart, brain, and other organs stop working until they thaw out and reanimate in the spring. It’s a pretty nifty chemical trick, on par with being able to transform your complexion at will. 

Kermit has an unmistakable personal brand, but distinguishing H. versicolor from H. chrysocelis visually is just about impossible. Both Eastern and Cope’s are relatively small (1.5—2.0 in/3.5—5 cm), and the adults are often mistaken for younglings. Both wear a sweep of bright citrus-orange along the inseam of their hind legs (a signature shade is all the rage, you know).  Females of both species are usually (but not always) larger, with a ladylike white throat. During the breeding season, males have a macho (make that hipster, since it resembles a beard) black, gray, or brown throat. Guys sing. Gals swoon, but don’t sing along.

The ranges of these two species overlap, but Cope’s are more widely distributed. If you find a gray treefrog in North Carolina or Georgia, you can be reasonably certain it’s a Cope’s, but if you’re in Iowa or Pennsylvania, all bets are off. The only risk-free way to know for sure is to do a DNA test — Cope’s are a diploid species, meaning they have two sets of chromosomes, one from each parent (for a total of 24); Easterns are a tetraploid species, meaning they have four sets of chromosomes (for a total of 48).

Now, some frog call connoisseurs claim they can detect variations in breeding calls, and that Cope’s treefrogs have a faster and slightly higher-pitched trill than Easterns. But the call rates of both species change with ambient temperature… so color me skeptical.

[Postscript:  What kind of frog is Kermit? While I’ve never found a definitive answer to this question, I always assumed that because he was created/discovered by Jim Henson, he was probably Hyla muppetalis or Rana hensonii… something like that. However, in 2015 Brian Kubicki of the Costa Rican Amphibian Research Center discovered a frog who, if not the same species, must at least be a first cousin, or possibly Kermit’s doppleganger.]

Diane’s bare-hearted glass frog (Hyalinobatrachium dianae). Photo: © Brian Kubicki, Costa Rican Amphibian Research Center, Used with Permission

[Thanks to the photographers who granted permission to use their photos, and to those who made their work available through the Creative Commons license: Dave Huth(composite of color variations), , Chiswick Chap & CheChe, (melanophores schematic), Alan Wolf, Andrew Hoffman, and Douglas Mills© 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

Multi-Tasker

I found a blue jay feather this morning while I was out walking my dog, Dash. That isn’t remarkable — jays are a common species here, and because the color blue is relatively scarce in the natural environment (except for the sky) it’s eye-catching. I’ve started an informal collection, compiled on some shelves near my front door. I admire them on a semi-regular basis while running a Swiffer™ over household surfaces, and when I have to pick them up off of the floor because I’m cleaning like it’s a timed event.

As I ambled along, spinning the feather between my thumb and forefinger, I could feel it lift at the slightest breeze, attempting to return to the sky. I started thinking about the versatility of this keratin assemblage, this trinket both delicate and durable, this multi-tasker extraordinaire.

I’m well aware that researchers say multi-tasking is a myth, at least when it comes to the human brain. We only think we’re doing several things at once, the scientists tell us; actually, we’re just toggling back and forth from one thing to another, which reduces our mental efficiency and even lowers (temporarily) our IQ.  I’m mostly convinced by these studies but, full disclosure, neuroscience isn’t my field so I’m only familiar with what’s summarized and reported by the media… and by “media” I mean NPR. In light of all that has been reported, though, I find it even more fascinating and frustrating that handling more than one task is trivial for so many other, less admired, anatomical features. Wouldn’t you expect our much-lauded gray matter to be every bit as masterful at multi-tasking as, say, a feather?

Think about it…

First of all, feathers allow birds to fly — a feat humans have still not managed to accomplish, even though we reassure each other constantly that we have the largest, most amazingly intelligent brains on Earth (clearly, though, ours is not the most self-confident computer on the planet).

Now, before you think I’ve somehow overlooked the fact that thousands of human beings are flying from one global location to another all day, every day, and have been doing so for quite some time, let me interject that human beings have, without question, figured out how to make machines fly (with the aid of metallurgy and fossil fuels, of course). But we have never, not once, jumped up from the ground or launched from a tree branch to flap off into the wild blue yonder. Superman doesn’t count because he isn’t human, and wing-suits don’t count either because that’s gliding, not flying. Humans ride, birds fly, and they do it by flapping feather-covered arms, using renewable energy sources like insects, berries, seeds, and sugar water.

Next, consider that feathers also provide thermal insulation. This should come as no surprise because people use bird feathers to keep warm, too. We stuff clouds of down and feathers in-between layers of rip-stop polyester made from recycled plastic water bottles to manufacture vests and parkas. Then we slip on the garment, zip up the front, and head out into the elements to do some birdwatching.

Birds can waterproof their feathers with bio-oils stored in a convenient uropygial/preen gland at the base of their tail. This is handy because, having allocated their arms to flying, they can’t hold a spray can of Scotchgard™. Nor are they able to use hammers, saws, and other tools to build a roof overhead that will shield them from rain, sleet, and snow, or to build a boat when they want to go fishing.

But wait— there’s more! Bet you didn’t know that feathers are also an effective communication device. See, humans use an broad assortment of products, including designer label clothing, team-sponsored gear, our vehicles, digital devices, and jewelry to make nonverbal announcements about our group affiliations and availability.

Birds accomplish the same thing using their birthday feather-suits. The colors and patterns they wear say more than any Tinder profile or list of Who’s Who ever could.  Female birds assess a suitor’s sartorial presentation to determine if he’s her type, and male birds parade their plumage to show the ladies they’ve got the goods to be a quality life-partner. Or maybe just a handsome hookup, depending on how the species swings. Those same feathers can be used to warn a trespasser that this territory has been claimed, or warn a romantic competitor to back off.

Kind of puts the old uni-tasking cerebral cortex to shame, don’t you think? And all this time I’ve been under the impression that “featherhead” was an insult.

 

[Thanks to the following photographers for making their work available through the Creative Commons license: bagaball, Richard Hurd, Jonathan Fox, Ingrid Taylar, and Putneypics.  © 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

Hot and cold

next-door nature, urban wildlife, fence lizard

Everyone, even fence lizards and other ectothermic creatures, are feeling the heat these days (Photo: Bandelier National Monument, Creative Commons license)

.

Temperatures across the southern half of the U.S. are soaring into triple digits, so I was trying to think of creative solutions to beat the heat when it hit me—why not become cold-blooded!

next-door nature, urban wildlife, fox squirrelAlas, my brain must have overheated. Once air conditioning allowed a cooler head to prevail I realized that what seemed like a brilliant idea while baking beneath a blazing sun is absolutely, completely, utterly impossible… and not simply because mammals cannot will themselves to undergo metamorphosis.

You see, technically there’s no such thing as a cold-blooded animal (unless you’re speaking metaphorically about someone who lacks emotion or empathy).  Or a warm-blooded animal, for that matter. Both terms are shorthand for the ways in which body temperature (aka thermophysiology) is controlled in different types of organisms.

Most mammals and birds are classified as endotherms (Greek: endon = within; thermē = heat). For these critters thermoregulation is an inside job, primarily by way of metabolic processes. Under extreme environmental next-door nature, urban wildlife, sunbathersconditions some physical mechanisms come into play, but not solar energy (at least, not directly). If the mercury plummets and the body’s core temperature begins to drop, muscles shiver to create warmth; if the core temperature starts to rise the body perspires to cool via evaporation. No sweat glands? Pant like a dog… or birds. All evidence to the contrary, since humans are mammals, swimsuit-clad sunbathers dozing in rows on a beach or poolside with icy drinks standing at the ready are, in fact, capable of maintaining a relatively constant body temperature.

next-door nature, urban wildlife, gray treefrogWhen an animal’s body temperature is strongly influenced by ambient conditions it’s an ectotherm (Greek: ektós = outside). Fish, amphibians, reptiles, and invertebrates rely on external heat sources to get their juices flowing, especially during the chillier seasons or cooler times of day. That’s why these animals can be seen basking on rocks, roads, and any other warmth-radiating surface. Then, when they can’t stand the heat they get out of the kitchen, retreating into shade, water, or underground to cool off (Sound familiar? We really are more alike than different).

Take-home message: mammals and birds are endotherms; invertebrates, fish, amphibians, and reptiles are ectotherms.

Except when they aren’t.

It’s the exceptions that make the rule, right? Let’s begin with the usual ectotherm suspects. According to one source, 2% of invertebrates are endothermic. Regrettably, the informant failed to name names but, in spite of the fact that spineless animals are not my strong suit, I did managed to chased one down—snails and slugs (Oops, that’s two… and “chased” may be overstating things).  Fish, being vertebrate species, are my regular beat so I can state with certainty that billfish (e.g., sailfish, marlins), tuna (Scombridae), one family of sharks (Lamnidae, including makos and whites), and one species of mackerel (Gasterochisma melampus) are endothermic… at least to some degree. I’ve yet to find a reliable report of an endothermic amphibian, but among the reptiles sea turtles exhibit both ecto- and endothermic traits.

next-door nature, urban wildlife, echidnaMoving along to the endothermic exceptions… Hummingbirds (Trochilidae), swifts (Apodidae), and common poorwills (Phalaenoptilus nuttallii) all experience periods of lower body temperature and metabolic rate; therefore, some biologists argue they have ectothermic traits. Additionally, there are mammals—certain rodents, a couple of lemurs, and many bats—that enter hibernation or estivation in response to low temperatures or drought, respectively. Then there’s the echnidna (Tachyglossidae), a “primitive” mammal from Australia that’s an ectotherm eleven months of the year and an endotherm during the month when it lays its eggs (Yes, eggs. If you like rule-breakers Australia is your Mecca. In the interest of time and space, though, we’ll have to save monotremes for another day).

What I’ve presented above is a fairly simplistic description of thermophysiology.  Why stop there? Because a more thorough treatment would require a good deal of nuance and a complicated discussion of sub-categories, not to mention a stiff drink (the current temperature is 99°F and rising—make mine a frozen margarita).  But since it’s so hot I’ll go ahead and venture past a toe in the water… up to my knees, but no further.

next-door nature, urban wildlife, elephant shrewOne subset of the endotherms are tachymetabolic (Greek: tachy = quick), organisms with a consistent and extremely high metabolic rate. Shrews (Soricidae) are a perfect example—diminutive beings with massive appetites, their metabolic rate is at least five times that of similarly sized ectotherms. Being able to snack non-stop and still rock a bikini probably sounds too good to be true. It is. Finding a constant supply of calories without access to fast food and grocery stores is no picnic. Bradymetabolic (Greek: brady = slow), which could easily be mistaken for bipolar disorder, is no bed of roses either. These organisms swing wildly between a high (when active) and low (when resting) metabolism, usually based on either external temperatures or food availability. (If you think someone else has got it better, rest assured you probably don’t know the whole story.)

As biologists refine our understanding of how bodies work, language evolves and once popular terms like cold-blooded fall from favor. Popular stereotypes suggest otherwise, but scientists are not completely immune to trends. When I was an undergrad, for example, the preferred word for organisms influenced by changes in ambient temperature was poikilotherm (Greek: poikilo = varied, irregular). Although still useful for making distinctions between types of ecotherms, the term is used less frequently now and may be on it the way out.

next-door nature, urban wildlife, crocodilesC’est la vie. Styles change, in both the lab and on the beach (Thankfully. I’m old enough to remember when Speedos were all the rage in men’s swimwear). I’d be willing to bet, though, that most Earthlings won’t give up sun worship any time soon. Chillin’ in a sunbeam feels too good, whether you need it or not (at least as long as there’s a pool nearby).

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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: Bandelier National Monument (sunning fence lizard); Michael V. Flores (fox squirrel cooling down); Nick Papakyriazis (sunbathers); geopungo (gray treefrog); BohemianDolls (elephant shrew); and Jess Loughborough (basking crocodiles).

Barnstormers

next-door nature, urban wildlife, suburban wildlife, barn swallows

The barn swallow is a spectacular aerial acrobat (Photo: Eugene Beckes, Creative Commons license)

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WITNESS astounding tricks of precision flying!

THRILL to the sight of daring aerial capers!

Come one, come ALL!

The Flying Circus is winging its way to a backyard near YOU!!

 

next-door nature, urban wildlife, suburban wildlife, barn swallowCritics are raving about this summer’s must-see event. Word to the wise, though—in addition to a lawn chair you’ll definitely want to bring some binoculars. That’s because the stars of this air show have an average wingspan of about 12 inches (30 cm). We’re not talking F/A-18 Hornets here, or even a Cessna 152. Think sparrow-sized, not Sparrowhawk.

Barn swallows (Hirundo rustica) epitomize the principle of “form follows function.” Combine a slender fuselage with long, tapered wings and a deeply forked stabilizer (aka “tail”) and you’ve got a bird made to spend the majority of waking life with wheels up. They even wear a uniform appropriate for fly-boys (and girls)—glossy chrome blue above and buff-to-rust below; similar to the colors of a U.S. Air Force Blue Angels jet.

Barn swallows are found far beyond U.S. borders, though.  You might even go so far as to call them jet setters. Six officially recognized subspecies are found in North and South America, Europe, Africa, and Asia. Generally speaking, the species breeds in the Northern Hemisphere (as far north as the Arctic Circle) and takes winter R&R in the Southern Hemisphere. Ornithologists have recorded barn swallows traveling over 7,000 miles (11,000 km) from Europe to southern Africa, and those based in the Americas cover similar distances.

next-door nature, urban wildlife, suburban wildlife, barn swallowWhether cruising inches above land or water or performing barrel rolls, loop-the-loops, spins, and stalls in mid-air, these agile flyers are crowd-pleasers. They aren’t grandstanding, though. A barn swallow’s life consists of more than playing with the physics of flight. Like the post-WWI stunt pilots of the 1920s, they’re trying to make a living.

It takes fuel to fly and the barn swallow go-juice of choice is winged insects—primarily high-octane flies, but also beetles, bees and wasps, next-door nature, urban wildlife, suburban wildlife, barn swallowmoths and butterflies, ants and termites.  Eating on the fly really comes in handy during long missions, including migration. Quenching one’s thirst, bathing, dating, and defending the home territory—they’re all done on the wing.

Historians disagree as to the origin of the term “barnstorming,” but one popular explanation is that pilots would fly through an open barn door and out the other side (they hoped) as a demonstration of their prowess and to drum up joy ride business.  Barn swallows have been known to fly in and out of barns as well—hence the common name. It’s a lot less risky for the birds, though.

Even daredevils like to have a place to call home, a chance to raise a family.  Before permanent man-made structures became commonplace, barn swallows built nests in caves or on the face of cliffs. Long tolerated by humans for reasons  both practical and aesthetic, today only one North American population holds to this tradition, in the Channel Islands off the coast of California; the rest of the fleet hangar in the rafters of open buildings or beneath porches. Bridges, especially those that span water, are particularly popular due to their proximity to crucial building materials.

next-door nature, urban wildlife, suburban wildlife, barn swallowGathering mud by the bill-full, mated pairs make countless supply runs to construct a neat cup or half-cup, depending on the location, then line it with grass, feathers, hair from the livestock living under the same roof, and any other soft, insulating materials they can find.

Once there’s a home base in the crosshairs, the bombardier gets the go-ahead to drop her payload of 3-7 eggs. The pair begin a series of aerial fueling attempts and in about a month’s time they’ve got themself a squadron of next-gen aviators.

Time to put on a show!

next-door nature, urban wildlife, suburban wildlife, barn swallow
.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!
© 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] Eugene Beckes (wings tucked; wings open); Julio Mulero (drinking); Dan Wilson Photography (nestlings); Eugene Beckes (swooping); Bill Lynch (muckraking); Mikael Dusenne (parenting); Pat Gaines (missile).
Barn swallows in flight:
Modern day barnstormer performing aerial acrobatics: