Wild With Nature

July 6, 2022

The burrowing owl watched me from the fencepost, then glanced away, eyes half-closed. Its mate was perching on the ground nearby, next to a black-tailed prairie dog burrow. It’s always a special day when I get to see burrowing owls.

It was late morning a week ago, just becoming hot and breezy. The place: my Breeding Bird Survey route, in farm country near Big Sandy, Montana. It’s always great to see burrowing owls, but this was a particular treat: my first sighting of them in this area since I first started surveying the route four years ago.

And seeing them near a prairie dog burrow was no coincidence. Burrowing owls nest underground; prairie dog towns give them nest sites. And burrowing owls aren’t alone.

By changing the landscape where they live, prairie dogs provide habitat for a unique community. In fact, these rodents are considered a “keystone species” because of all the life their presence supports. Black-footed ferrets (Mustela nigripes), which have become extremely rare, utterly depend on large prairie dog colonies for their survival. Burrowing owls and mountain plovers are strongly associated with prairie dog towns. Horned larks are common in these habitats, as is the insect-eating northern grasshopper mouse (Onychomys leucogaster). Golden eagles and ferruginous hawks often stop by to hunt prairie dogs.

Disappearing habitat

Prairie dog towns used to be much more common across the Great Plains than they are today. Estimates vary, but some researchers suggest that in 1900 they covered as much as 98 million acres across the west. Since then, habitat loss, disease, and poisoning have taken a dramatic toll. Prairie dogs continue to survive here and there. But their decline has been so steep that they are now “functionally extinct” in terms of their role in the grassland ecosystem.

The Helena Valley, where I live, is no exception to these general trends. But on the north side of the valley, along Interstate 15, a prairie dog colony has persisted for many decades. The colony was already there when Last Chance Audubon Society published the booklet Birds of the Helena Valley in 1979. Then, the authors wrote that the area “often support[ed] a pair of burrowing owls.” But in the 43 years since then, it seems, the burrowing owls have disappeared. No one has reported them here since 1979.

What has changed? Have the burrowing owls actually disappeared? Or have they just been here all along, hiding from local birders?

Today, on this early July morning, landowner Mike Hossfeld has very generously given me permission to take a look around. I’m looking for prairie dogs, owls, and whatever I can learn about this unique habitat. I’m hoping for a repeat of last week’s experience near Big Sandy. Will I find a pair of burrowing owls here? Honestly, after 43 years, it doesn’t seem very likely. But I can hope. And burrowing owls or not, there’s a lot we can learn from a prairie dog town.

Near the edge

So here I am, at sunrise, standing near the edge of the colony. Although the town is still active, the prairie dogs have abandoned this edge of it. But even so, the signs of them live on. In the green areas between swaths of sagebrush, the plants tell of how the prairie dogs shaped this spot before they disappeared.

Dotting the area are a variety of low-growing perennials. These are a few of the characteristic plants that thrive on an active prairie dog town: scarlet globemallow (Sphaeralcea coccinea), western wheatgrass (Agropyron smithii), fringed sage (Artemisia frigida), Sandberg bluegrass (Poa secunda), flaxleaf plainsmustard (Schoenocrambe linifolia), and pingue rubberweed (Hymenoxys richardsonii). Meanwhile, the rankly growing annuals reaching for the sun – Russian-thistle (Salsola sp.) and orach (Atriplex sp.) – tell us that the prairie dogs have left. Without these grazing rodents, the annuals can grow tall.

Now I’m approaching the active edge of the town, leaving the shrubby sagebrush behind. The vegetation becomes dominated by a low, silvery-green, herbaceous carpet of fringed sage (Artemisia frigida). The thick stands of tall annuals fade away. From the direction of the interstate, a lone pronghorn is watching me, giving an occasional low bark.  Above the traffic noise, the tinkling voices of the horned larks are the song of this place. They mingle with the whistles of the western meadowlarks and the melodic trills of a vesper sparrow. A robin is chipping insistently from the fence.

Merlins, larks, and sparrows

The robin continues to call from the fence, broadcasting his annoyance. Then I spot him, and I realize why: two fenceposts away from him, a merlin is perching, too. She soaks up the early morning light, steadfastly ignoring the robin. He can’t afford to be so nonchalant: merlins feed primarily on birds. The presence of this slender falcon has put him on high alert.

Closer to me, a horned lark is perching on the fence. Another is singing overhead, an exuberant cascade of chips. He sails through the air high above me, his black tail spread wide. 

In the distance, from a patch of sagebrush that follows the draw along the edge of the prairie dog town, I can hear another familiar song. It’s a series of gentle, musical trills, cascading towards my ears. Farther away, another begins to sing. They’re Brewer’s sparrows, at least three of them greeting the morning from the sagebrush. Unlike the area I visited last month at Devils’ Elbow, there’s enough sagebrush left here to support these habitat specialists.

Now there are six pronghorns watching me from the west: a string of fast-footed sentinels, chuffing occasionally. Another band is grazing in the shadow of the hill to the north, their white rumps glowing in the still light of the morning.

Getting closer

I still haven’t seen or heard a prairie dog. But where I’m standing now, I can tell that their burrows have been recently used. The mounds poke up from the earth like enormous pimples. I walk over to one of them for a closer look. No plants have started growing yet on the sloping sides of this mound, except for an occasional globemallow and an opportunistic Russian-thistle. But nevertheless, the prairie dogs that lived here are gone. The entrance to the burrow is filled with spiderwebs.

Where are the prairie dogs? Between the abandoned mounds, the feathery green Russian-thistle is growing up between gray cushions of fringed sage. The rodents haven’t been here this year to trim it. A horned lark is on the ground nearby. He pauses to sing, runs a few steps, then pauses again. Occasionally he taps the ground with his beak, mixing a bit of foraging among his morning songs. Suddenly another male appears, making a low pass at him. The ground-based singer leaps into flight and his rival chases him 50 yards in a flurry of wings and calls. Then it’s over, as quickly as it began. The males land separately and resume their singing.

And there to the east, backlit by the yellowing sun, I see the morning’s first prairie dog! This one is lounging quietly on its burrow, resting on all fours. Around it is a low sea of fringed sage. This carpet extends 100 yards farther east, where the big sagebrush rears up in a thick, shrubby tangle. Is a coyote lurking there, hoping to sneak up on the prairie dog? Not this morning, it seems: the Brewer’s sparrows continue to sing, their musical trills undisturbed by predators in the sagebrush.

Prairie-dog plants and geologists

I walk past another abandoned burrow entrance, its slopes overgrown with succulent, leafy foliage. This plant is another annual, Monolepis nuttalliana. Someone has given it the entirely unflattering common name of “Nuttall’s povertyweed.”

How tragic. So many of our native plants, Monolepis included, have been cursed with unpleasant names in English. So many of these names contain the word “weed.” It’s as if the settlers arriving on this landscape were capable of imagining nothing but weeds. For Monolepis nuttalliana, I just can’t stand to call it “Nuttall’s povertyweed” any more. But fortunately, common names of plants are established by usage, not by rules. For a plant like Monolepis – which no one really calls by its common name, anyhow – changing the name is as easy as starting to use a different one. So how about “succulent prairie-dog plant”?

The prairie dog who built this burrow was clearly a geologist. While the surrounding soil is fine-textured and silty, this mound is a collection of angular shale fragments, a midden of grays and reds. A chunk of shining white quartz lies at the edge. This geology-minded rodent was a subsurface miner, bringing up rocks from deep within the soil profile.

Calls of alarm

I leave the abandoned burrow of the geologist behind. 40 yards ahead, a prairie dog has started chipping at me. It’s a low, sharp call repeated many times in a fast, stuttering succession. Two more prairie dogs are standing upright on a burrow farther ahead, and one of them starts chipping at me as well. I’ve reached prairie dog land.

I walk towards the pair. One of them dives underground, but the other remains undecided. She submerges herself partway, just showing me the top of her head above the volcano-like burrow entrance. She keeps chipping at me, a bit hesitantly now. 

(Note: I don’t know for sure that this individual is a female. Since she didn’t seem to have testicles, and I refuse to call her “it,” I’m treating her as a female for this article. I think I’m right – but I’m not a prairie dog biologist. As far as I can tell, determining prairie dog sex from field observation is usually difficult, though there can be behavioral cues. Do you have any thoughts on this? Let me know!)

I decide to sit down where I am and watch her. Her chipping becomes even more hesitant. Eventually she quiets and just sits there, watching me back, her black eyes gleaming with awareness and what seems like curiosity.

Fringed sage: not a salad green

The vegetation around her is manicured: a prairie dog lawn. Low carpets of fringed sage alternate with blue-green swaths of western wheatgrass. The fringed sage is starting to send up leafy stems, preparing to flower. But what’s that there? A pile of these stems is lying on the ground, cut down by a prairie dog.

I kneel low to the ground, putting my eyes at the height of a prairie dog in “bowling pin posture” (this is what I call it when they stand upright). From this height, you can see a coyote or badger approaching from as far away as the next prairie dog neighborhood. From the raised top of a burrow entrance, the view is even better: you can see as far as the human dwellings beyond the town, surrounded by their shelterbelts of Russian-olive.

It makes sense that the prairie dogs would clip the fringed sage stems to maintain this visibility. This way, it’s much harder for predators to sneak up on them. But why aren’t the prairie dogs eating the sage? When I crush a leaf, I notice that it has a pleasant herbal smell, rather like camphor. I try nibbling on it. The taste: well, it leaves a bit to be desired. The leaves are soft and a bit furry, with a flavor so intensely bitter that it makes my tongue water.

Nibbling on a few leaves might be an interesting sensation, but I’d hate to have to eat a fringed sage salad. Apparently the prairie dogs agree: this is an obstruction to clear, not a food to enjoy.

Watching skeptically

Here and there, I see grasses that have obviously been grazed. The grass leaves have been eaten, not trimmed. Apparently western wheatgrass and blue gramma are tasty snacks to a prairie dog’s palate.

The nearby prairie dog is still very skeptical about me. Now she has sunk down into her burrow so that only the very tip of her head is showing. 

A hundred yards away, though, a prairie dog family has decided that this strange mammal with the camera isn’t dangerous. For now, at least. Five prairie dogs have emerged from this burrow. Four are clearly smaller than the other: is this Mom with pups? They sit on the mound, soaking up the morning sunshine. Two of the pups tumble off to play: not too far, though. Mom is grooming one of the other youngsters, washing the fur on his back. The pup turns around and tries chewing on Mom’s tail, then tries his litter mate’s tail.

The female who is closer to me is still acting wary. Slowly, she emerges from her burrow. Then she perches on top, watching me, just an eyeblink away from safety underground. She waits calmly. There’s no hurry. It would be nice to forage for some breakfast – but she’d much rather wait than find out that I’m dangerous and become my breakfast. 

Building trust?

Farther off, the prairie dog family has spread out to forage. They’re still close to safety: it’s a quick ten-yard dash back to the mound. They’re foraging in an area where there’s lots of fringed sage, but from here I can’t quite see what they’re eating. Mom returns to the mound for a minute, foraging along the edge, and I get a slightly better view. She’s on all fours while she gathers her food. Then she stands up to chew, looking around for predators while she eats. 

The nearby female eases down from her perch on top of the mound. She’s still not sure about me, but she seems pretty relaxed now. She lies down, sunbathing at the edge of the mound. Eventually she yawns, stretches, and begins to feed – cautiously. I raise my camera. Whoa – that was too much. Offended, she races back to her bowling pin posture, standing at the top of the mound. 

Okay, I’m sorry! Gaining a prairie dog’s trust clearly takes time. I go back to ignoring her and watching the distant family. Two of the kits are playing on their mound like puppies, jumping up and pushing each other. 

A second chance

The nearby female decides to give me another chance. She moves out to the edge of her burrow on all fours and starts feeding. She nips a mouthful of vegetation and then stands on her hind legs, using her front paws like utensils to help her eat. I’m watching with just my peripheral vision right now. No eye contact, no threatening movement of my binoculars or my camera. Without magnification, I can’t see what she’s eating. Slowly, I raise the binoculars.

She tolerates it for a second, then gets nervous. Instead of returning to her burrow, though, she bolts towards another. This second burrow is just slightly farther away, but much more to my side. I have to twist awkwardly to watch it.

Now it doesn’t take her long to start feeding again. Eventually, I raise my binoculars. This time she lets me. She’s working on a leafy mouthful of succulent prairie-dog plant, Monolepis nuttalliana. It rapidly disappears between her furry black lips.

I raise my camera. Okay, if you must, she seems to say. The angle is awkward. I’m twisted sharply to my left. My back is cramping up and the camera keeps wobbling against my knee, but I don’t want to turn my knees towards her and startle her.

She’s busy with western wheatgrass leaves now. She’s shoveling them into her mouth, one at a time, like slim green carrot sticks. Often, she stands up to eat. Sometimes she stays prone, lifting one front paw to hold her food as she chews. When she moves, her gait is an endearing waddle, like a well-fed gardener fondly picking her way through the vegetables.

Time to go

A few minutes later, she turns around and starts barking again, softly. I look around: where is the intruder? I don’t see anything: no hawks, no badgers, no foxes, no coyotes. Then I realize she’s barking at me. Has she gotten so engrossed in her breakfast that she’s forgotten I’m here? Or has she just gotten tired of putting up with letting me watch her eat?

In either case, her point is clear: I’m no longer welcome here. As I stand up and start walking away, she intensifies her barking. The family in the distance joins in. They’re all on alert now, Mom and the pups perching on three different burrows. All five have their heads up, and Mom is in the bowling pin pose.

Briefly, I swing west through the rest of the active town to count prairie dogs and look for burrowing owls. Other neighbors join in the barking, yelling at me from their burrow entrances and jerking their tails. This is the “welcoming committee” a prairie dog town presents to intruders: we see you! Go away!

Prairie dog disappearances

I haven’t seen any burrowing owls this morning. And farther west, the barking of the prairie dogs stops. There are burrows here, but they’re all abandoned. The fringed sage, western wheatgrass, and blue gramma of the active town have all but disappeared. In their place, this area is a field dominated by annuals, mostly Russian-thistle and goosefoot (Chenopodium sp.). Where have all the prairie dogs gone?

Across their range, prairie dogs face many threats. Sylvatic plague, introduced to North America around 1900 in the fleas of ship rats, can wipe out whole colonies of these social rodents. But even in the absence of sylvatic plague epidemics, the size of a prairie dog town can fluctuate substantially from year to year.

Pests?

Since my great-grandparents and other Europeans settled the west, it’s become common to consider prairie dogs as pests. People say that they compete with livestock, eating the same grass. To kill them, land management agencies have hired people to poison prairie dog towns with zinc phosphide or aluminum phosphide. In the digestive system of an animal – prairie dog, bird, or human – these compounds react to produce phosphine, a highly toxic gas that kills the body from the inside. Prairie dog shooting has also become popular – a leisure activity that is supposed to help ranchers.

But are prairie dogs pests? Certainly a burrowing owl would disagree. As for whether they compete with cows, a closer look at this question shows that it depends. The climate, the particular grassland, density of cows, density of prairie dogs, the weather of a particular year: all of these can change the answer. In some cases, cows and other ungulates actually prefer prairie dog towns over other rangelands. The forage, cropped low and fertilized with prairie dog dung, can be lusher and more palatable than it is elsewhere. In other cases, the presence of prairie dogs may reduce the density of livestock a range can support. (But poisoning, which is usually paid for by taxpayers for grazing allotments on public land, costs more than it would to tolerate prairie dogs and compensate ranchers for any loss of forage.)

Looking ahead

After a morning in this prairie dog town, it seems that I’ve only scratched the surface. Are there grasshopper mice here, as there apparently are in many towns? Do burrowing owls still inhabit this spot in some years? (And will they next year?) Do golden eagles and ferruginous hawks hunt here during fall migration?

Why do prairie dog populations fluctuate so much from one year to the next? Two centuries ago, were there other prairie dog towns in the Helena Valley?

Perhaps in a few more years, answers to some of these questions may become clear. Others will remain unknown. And undoubtedly, there will always be more that prairie dogs can teach us.

In the meanwhile, I’m glad that this town is still here. Thanks to Mike Hossfeld and other tolerant landowners, prairie dog pups still tumble around and chew on Mom’s tail, just a few miles from the state capitol. And maybe next year, the burrowing owls will be back.

Further reading

Elbroch, M. & K. Rinehart. (2011). Behavior of North American mammals. New York: Houghton Mifflin Harcourt.