Watchdogs

I heard sharp calls piercing the air, even before I noticed the compound of earthen dwellings, and knew that sentinels had spotted me and my canine companion.

Last autumn, I spent some time in New Mexico. I lived there, between Albuquerque and Santa Fe, for nearly a decade about 10 years ago, and I’d been feeling nostalgic for the high desert, with it’s technicolor sunsets and scents of piñon smoke and roasting chiles. So I packed up the car, settled Dash into his travel crate, buckled my seatbelt, and drove west. I wanted to spend some time catching up with friends over pozole and stacked enchiladas, making a pilgrimage to my favorite spa, and watching for urban wildlife species that are notably absent from my current home-base in Virginia’s New River Valley.

The terrier-boy and I were walking along a suburban easement one afternoon, behind a neighborhood of faux adobe Pueblo Revival style homes, when the cautionary cries began to fly. The barked alarms were not coming from man’s best friends—the backyard pooch patrol was decidedly silent. Maybe they were on a coffee-and-donuts break, or just taking a siesta. All I can say is, residential security companies and neighborhood watch associations could learn a thing or three about vigilance and civilian defense from the citizens of a prairie dog community!Based on old cowboy movies, you might think a drive far beyond the city limit sign would be required to find a prairie dog town, but these southwestern  hobbits have adapted admirably to humans and our sprawling developments. I guess that shouldn’t come as a surprise—after all, we have a good deal in common. Like H. sapiens, prairie dogs (Cynomys spp.) are social mammals. Like people, they can and do organize for the common defense. And, similar to their bipedal neighbors, they’ve developed a sophisticated vocal communication system.

Despite their common name and distinctive bark, these watchful creatures are not canines, but a type of ground squirrel native to North American grasslands. There are five different prairie dog species found in the U.S., Canada, and Mexico: black-tailed (C. ludovicianus), white-tailed (C. leucurus), Gunnison’s (C. gunnisoni ), Utah (C. parvidens), and Mexican (C. mexicanus). While best-known for their namesake call, this burrowing band is no one-hit wonder.

According to research by Constantine Slobodchikoff, Professor Emeritus at Northern Arizona University, prairie dog calls vary based on the type of predator (e.g., coyote or domestic dog, hawk, snake, or human). They even construct sentences, complete with a form of grammar, to convey specific information about the approaching menace, including color, shape, size, speed, and direction. Not a generic “Danger, Will Robinson!” SOS, but a detailed threat assessment along the lines of “Heads-up everyone! There’s a short, square-shaped, white-furred dog and a medium-tall human wearing a blue Marmot fleece jacket approaching on foot from the southeastern quadrant!”

How did researchers learn to decode Cynamysian? (Hey, if you have a better name for the language of prairie dogs, I’m all ears.) By presenting an imitation predator and observing the call and response. For example, the alarm call for “diving hawk” causes all the prairie dogs beneath the flight path to dive for shelter, while those outside the path calmly stand and watch. When a sentry sounds the “coyote or domestic dog” call, everyone above-ground moves toward a burrow, everyone below-ground comes to the surface, and then they all stand near the entrances, rubbernecking. “Human,” on the other hand, must be the equivalent of “CODE RED!” because the whole damn town runs for cover.

Dr. Slobodchikoff found that prairie dogs create new calls to communicate with one another about novel objects. They even engage in social chatter that has nothing whatsoever to do with existential threats to individuals or society. This small talk has been harder to decipher, but I suspect it includes all the gossip greatest hits—friends and family, crushes and break-ups, insults and resentments.

The social nature of a prairie dog town may explain a cultural phenomenon I think of as the Cynomys Wave. This conspicuous (and apparently contagious) behavior, also known as the jump-yip, begins when a single resident spontaneously stands on its hind legs, stretching up and back as if beginning a sun salutation asana. Instead of chanting OOOMMM, however, the creature let’s rip with a high-pitched WEE-OO, similar to the infamous yell that ended Howard Dean’s presidential aspirations . Then, in a scene reminiscent of a circa 1977 football stadium, the whole town jumps up to do The Wave, squealing like demonic dolphins.

Some scientists have hypothesized the jump-yip has a territorial function, as in “Mine, mine, this magnificent mound of excavated soil is MINE, and don’t you forget it!” Others suggest it’s related to alarm calls, serving as an “All clear!” once a crisis has pasted. A definitive diagnosis remains elusive but, regardless of its true purpose, it is certainly attention-grabbing.

Humorous antics aside, not all humans are happy when prairie dogs move into the neighborhood. For example, the sort of person whose self-worth is tied to an manicured, emerald green lawn of putting green smoothness is unlikely to put out the welcome mat for any subterranean species.

Nevertheless, prairie dogs do provide an accidental altruistic service to the larger environmental community, including people: they act as khaki-furred “canaries in the coal mine” for a very specific zoonotic disease. When there’s a sudden die-off in the local prairie dog population, it’s a strong indication that plague (of bubonic fame) has come to town. In some states, Health Department personnel regularly visit prairie dog communities, sampling the burrows for fleas, which carry the Yersinia pestis bacterium. The blood-sucking insects are then tested for plague as a proactive management strategy.

The development of modern antibiotics have lessen the impact of plague on human populations but the disease remains devastating to prairie dogs, inflicting far more damage to the community than mammalian, avian, or reptilian predators. Knowing this, I can’t help but wonder if Dr. Slobodchikoff’s team ever discovered a unique alarm call for fleas.


Life is better with Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

© 2018 Next-Door Nature. Reprints welcomed with written permission from the author. Thanks to Alan Howell of Star Path Images for granting permission to use his photo, and to those who made their work available through the Creative Commons license: Josh MoreLarry LamsaToshihiro Gamo, Thomas, and William Currier.

Virtuosity

Maybe Bobby McFerrin was a house wren (Troglodytes aedon) in a previous life.

This thought popped into my mind when, after listening to On Being’s Krista Tippett interview the singer, I went out for a walk with my canine companion. We hadn’t made it too far down the sunny trail when we were suddenly drenched by a deluge of liquid notes. That vocal tsunami, pouring forth from an entirely disproportional feathered Dixie cup, stopped me in my tracks.

Like McFerrin, who is known for fluid, polyphonic singing and quick, oceanic octave jumps, the wren’s song bounced around like raindrops on pavement. I suppose that’s why the synapses in my brain connected the two muscians.

There are definite differences between these gifted songbirds, though.

For example, wrens and other passerine birds produce vocal sounds using an organ called the syrinx, positioned where the trachea splits into two bronchial tubes. Each side of the syrinx operates independently, so songbirds can produce a sweeping range of notes in fractions of a second, or two different pitches at the same time, or simultaneous rising and falling notes, all without stopping for a breath. Humans, by contrast, make vocal sounds by sending air from the lung into the windpipe, through folds (aka vocal cords) in the larynx, and out to the throat, nose, and mouth.

Admittedly, McFerrin often sounds as if he has a syrinx but, hard as it is to believe, he’s making all of those notes with the same equipment you and I have. It’s just that he’s playing every instrument in the orchestra, and we’re barely pecking out “Chopsticks.” His ability to switch pitch is inarguably stunning; however, even this virtuoso can’t match the speed of a wren running through the scales.

McFerrin has a rich and ever-expanding repertoire that includes pop, a capella, choralclassical, spirituals, and movie scores. Like any jazz artist worthy of the title, he is a master of improvisation; always learning, always expanding his technique, consistently creative and ready to try something new. Wrens, on the other hand, may sound like they’re jamming but they’re actually shuffling 12-16 stock syllables… kind of like a classically trained musician who learned to play according to the rules of the conservatory but wants to sound cool enough to swing.

You see, passerines begin their musical education when they are barely out of the egg, during a development phase known as the critical period. Listening to the adult birds around them, the youngsters tune in to the songs and calls of their own species. Once young wrens have left the nest they practice, over and over and over, dialing in the sounds until the song matches the memory. With the exception of mimicking species (e.g., mockingbirds, catbirds, and thrashers), there will be no extemporization. That’s because wrens choose a mate based on the ability to cover “their song” note for note. Some bird songs have geographic variations, sort of like regional accents, but chicks want a boy who sounds like he’s from the neighborhood, and will pass over anyone who sounds too exotic or experimental.

I’m much less discriminating, at least on that score. Bubbling, effervescent singing, whether it’s an improv by McFerrin or a house wren standard, always helps me tune out my worries… and that makes me happy.

[Play both videos at once so Bobby and the house wren can duet!]

 

[Thanks to the following photographers for making their work available through the Creative Commons license: Dustin Gaffke, , Todd Van Hoosear, and Rachid H.  © 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]