July 12, 2022

As soon as I step out of the car, the smell of the sagebrush washes over me. It’s a heady smell, bitter and somehow magical. It’s a few minutes before sunrise. The eastern sky is pale gold, fading to blue overhead. A chorus of birdsong floats over the sagebrush. Vesper sparrows are whistling and trilling from every direction. Brewer’s sparrows are singing their exuberant phrases. Occasionally I hear a meadowlark in the distance. A sage thrasher chatters repetitively, apparently nearby but out of sight. 

A raven croaks as it flies into the distance. Far away, the sandhill cranes are bugling. The sagebrush stretches for a mile and a half across this gently undulating flat, all the way to the base of the hills. There it becomes patchier, meandering up the draws, mixing with grass-covered hillsides. 

I’m near Silver City, where the range stretches unbroken for miles. Local rancher Ed Chevallier has generously given me permission to observe here this morning. What does this sagebrush community have to teach us today?

Sunrise in the sagebrush

I walk towards the sunrise, through an area where the sagebrush gets a bit sparser. Here, vesper sparrows are the dominant birds. Between the gray-green shrubs, I can see the loamy soil, dotted with angular pebbles. A male northern harrier is flying over. I notice a gap in his inner primaries where he’s molting his flight feathers. 

Minute by minute, the planet turns. At this time of the morning, I can see our rotation in the quiet movement of the sun as it creeps over the mountains. All of a sudden, the first rays of light are sweeping across the sagebrush. In the distance, where the shrubs get denser, a few Brewer’s sparrows have resumed their singing.

Short clumps of broom snakeweed (Gutierrezia sarothrae) are beginning to glow a bright spring green among the blue-gray sagebrush (Artemisia tridentata). The grasses are sparse, a diffuse scattering of western wheatgrass (Agropyron smithii), blue gramma (Bouteloua gracilis), and Sandberg bluegrass (Poa secunda). Among old cow pies and the occasional clump of prickly pear, thousands upon thousands of bitterroots (Lewisia rediviva) are nodding, their flowers closed tight. Many have already finished blooming. Their flowers have dried out into papery seed carriers. When the wind gets strong, they’ll tumble across the ground, spilling out their seeds.

Morning songs

As I walk onwards, the sagebrush gets denser and lumpier. Some of these bushes look like two-story houses, with multiple levels and turrets near the top. The song of the vesper sparrows has faded into the background. Among these denser shrubs, the Brewer’s sparrows are singing, their enthusiastic voices cascading all around me. These are their “long songs,” the elaborate series of trills they give early in the day to claim and defend their territories. Later, they’ll grow quiet or shift to the simpler “short songs,” sung mostly by males who haven’t found a mate. Farther east, a sage thrasher is singing. His song sounds like an enthusiastic stream, bubbling here and splashing there. He lingers on one phrase, repeating it over and over, then moves on to the next.

For all of the songs swelling around me, I haven’t gotten a good look at a single bird yet. The songs carry remarkably well across the sagebrush. But when I get closer, the Brewer’s sparrows pause their singing, switching to sharp, dry chip calls. They fly up as I approach, scattering like ghosts. And though I’m not getting good looks, I can tell that there are lots of them around, and not just singing birds. Likely, many of this year’s young have already fledged.

There’s a time each year, near the middle of July, when it suddenly becomes apparent that many of our birds are done singing for the season. The morning chorus, such an energetic presence on the landscape through the spring and early summer, becomes muted and hesitant. But this morning, the lively songs continue to float in from the distance. We haven’t reached the songless season yet, though we must be close.

Sparrows and thrashers

A vesper sparrow is chipping anxiously behind me, flitting from sagebrush to sagebrush. This bird has a wasp in her beak. She is evidently waiting for me to leave; she must be feeding young in a nest nearby. Apparently not all of the young sparrows have fledged yet.

I leave the vesper sparrow to her feeding and start walking north. I’ve been hearing another sage thrasher singing vigorously from this direction, but I haven’t glimpsed him yet. His exuberant but elusive warbling continues. I keep walking, weaving between the sagebrush clusters. Each time I think I’ve reached him, his song seems to recede into the distance.

Finally, I spot him. He’s still far to the north, perching conspicuously in the top of the sagebrush. His song is loud enough that it carries at least twice the distance of the Brewer’s sparrows. And that is why I was having so much trouble finding him.

I angle closer and sit down about 50 yards away. Sometimes, the best strategy for finding birds is to stay in one place and be quiet. Which birds are using this patch?

Birds of the sagebrush

A second sage thrasher is singing to the north. The nearby male flies, making a series of low, bobbing swoops, and lands in the top of another sagebrush. He’s already singing again as he lands, his wings held half-open for a few seconds in a conspicuous display. Among his bubbling phrases, I keep hearing a distinctive whistle: cur-leeww! It sounds almost exactly like the call of a long-billed curlew. In his enthusiasm, this male has blended an excellent imitation of a curlew into his song.

A Brewer’s sparrow lands near me and flits methodically through the upper layers of the sagebrush. A few minutes later I see this bird again, back in the same area. It’s carrying a small insect in its beak. There must be a nest somewhere close.

Brewer’s sparrows, sage thrashers, and vesper sparrows: together, these birds form the voice of morning in the sagebrush. But actually, each one is telling a very different story. 

Brewer’s sparrows are sagebrush specialists. They hunt insects among the shrubs and build cup nests among the branches to shelter their lightly speckled, blue eggs. Sage thrashers also specialize in sagebrush habitats, choosing large, dense patches. But they hunt insects on the ground. On the other hand, vesper sparrows are generalists of open habitats. As the sagebrush gets dense, vesper sparrows become scarcer. These birds hunt insects and seeds on the ground. Grasshoppers and beetles can be prominent in their diets. And while Brewer’s sparrows nest in the sagebrush, vesper sparrows nest on the ground underneath. When it comes to nesting sites, sage thrashers are more flexible. They build their homes either on the ground or in the sagebrush.

Bird food

As I wander through the sagebrush, I keep looking for nests. I check the branches. I check the ground underneath. But so far, these birds have hidden them well.

The magical light of the sunrise has left. The sagebrush looks gray and resilient under the white morning sun. A male Brewer’s sparrow gives me a close look at him as I walk past his territory. Now he’s singing his mundane, two-buzz “short song,” not the ecstatic run-on trills of the “long song” that I was hearing earlier.

As the morning heats up, my thoughts turn to food. Not my own food. (Though I do think about that frequently, too). Right now, I’m wondering about bird food. What’s available for these sagebrush birds to eat?

I think again about the differences in these birds’ diets. Brewer’s sparrows feed on insects within the sagebrush foliage. Sage thrashers hunt insects on the ground. Vesper sparrows search the ground and the shrubs, looking for insects and seeds.

But seeds today seem few and far between. I’ve seen ripe bitterroot seeds here and there, still held in their papery parachutes. A few pussytoes (Antennaria sp.) are ripe, each tiny brown seed sporting a cottony tuft so that the wind can carry it. But I see no grass seeds, no sagebrush seeds. At this time of year, it seems that invertebrates must be the most important food sources here.

Having spent a day last month searching for insects on chokecherries, I know that I’m horrible at hunting insects on foliage. I’m constantly in awe of the way these tiny birds manage to find food. Unlike them, I’m not an experienced micro-hunter. I can’t see ultraviolet light. I’m not a Brewer’s sparrow, and my family’s survival doesn’t depend on my ability to find tiny insects.

Nevertheless, today I’m going to do a visual search. What’s here that I can see?

Jackrabbits and ladybugs

I keep walking among the sagebrush, looking for insects and hoping to find bird nests. Suddenly, there’s a flurry of movement a few feet away. A white-tailed jackrabbit leaps up from its scrape in the shade of an overhanging sagebrush. It bounds away, showing off long ears edged in black. As I stop to investigate the jackrabbit’s resting place, I notice a few seven-spot ladybugs (Coccinella septempunctata) resting on the sagebrush. What are they doing here? Where I find ladybugs, I usually find their aphid prey, but I haven’t seen any aphids yet this morning.

Nearby, crawling up a woody stem, I spot a transverse ladybug (Coccinella transversoguttata). Unlike the seven-spot, this is one of our many native species. In Alberta, biologist John Acorn writes that when the seven-spot ladybug was introduced, transverse ladybugs declined sharply. But around Helena, both species still seem to be common.

All of these red and black ladybugs must be at least as obvious to a sharp-eyed Brewer’s sparrow as they are to me. And they don’t move very fast when I approach them – so how do they all avoid getting eaten?

A bitter taste

I suspect that these bright colors must be a warning – do ladybugs taste horrible? I debate this with myself for a while, but I don’t see how I can avoid testing it. Finally, I make my decision. I apologize to the ladybugs. Then I pluck a seven-spot from the sagebrush. I thank it for its life. With quite a bit of hesitation, I pop it in my mouth and chew.

Honestly, it’s not as bad as I was expecting. It’s unmistakably bitter, for sure. But it doesn’t leave my mouth feeling numb like the aphids did last month. In fact, it tastes rather like a toned-down version of a sagebrush leaf.

Now I nibble on a sagebrush leaf, just to be sure. Yes, the bitter flavor seems very similar. But then again, wouldn’t all of the caterpillars, bugs, and other insects on the sagebrush end up assimilating these bitter compounds as well? Wouldn’t Brewer’s sparrows get used to them?

A study from the United Kingdom suggests otherwise. In this study, researchers artificially fed seven-spot ladybugs to blue tit nestlings. These baby birds fared poorly compared to the other blue tits in the study. Some even died of liver damage. This is one of the reasons I’m a field naturalist: sometimes experimental science, for all that it may teach us, can seem horribly cruel. In any case, the takeaway: seven-spot ladybugs aren’t joking with their warning coloration! Presumably Brewer’s sparrows avoid them. Next time, I will too.

Spittle in the sagebrush

As the morning heats up, I decide to count the ladybugs – and they’re proving to be quite common here! With every patch of sagebrush I pass, I tally a few more.

While I’m counting ladybugs, I also notice that the sagebrush is dotted with strange, foamy white structures. They look exactly like small, glistening gobs of spit among the leaves. And they’re quite a bit more abundant than the ladybugs. I don’t even consider sampling these for flavor.

But I do clip a spit-covered twig from the sagebrush and remove the foam. Inside, as I suspected, is a docile, 3 millimeter long insect. Its front half is brown, its rear half cream-colored. It has no wings. Next to it, there’s a centimeter-long cut in the bark of the sagebrush twig. This insect is a froghopper (superfamily Cercopoidea). Young froghoppers, or spittlebugs, make their frothy homes as a byproduct of their feeding. While they suck sap from their host plant, they also exude some of it from their anus. From this sap, they blow bubbles, creating a home in which they hide from predators. Gardeners, be thankful deer don’t do this! They’d have to eat more plants to exude this sappy covering – and how scary would it be to watch ghostly, deer-sized spit blobs floating around your yard, leaping over the fences and eating the tulips?

The froghoppers are abundant here. I can see dozens of them on each sagebrush plant in sight. Are the Brewer’s sparrows eating them? 

According to a guide to Canadian spittlebugs, birds primarily feed not on the froth-covered nymphs, but on the rapidly-hopping adult froghoppers. Still, the biology of these insects is not well-studied, so who knows? If you see a bird probing spittle clusters for food, let me know!

The seen and the unseen

A large black wasp is resting on a sagebrush stem. I get several photos of it before it flies. Is this what I saw the vesper sparrow carrying earlier?

I spot several interesting galls on the sagebrush. Gall-forming invertebrates are an entire world of their own, a mind-blowing variety of specialized insects and mites. They cause their host plants to grow weird structures (the galls), which these creatures use for protection as they develop. Big sagebrush hosts a variety of gall-formers.

But accessible, tasty insects are proving hard to find today. Once again, I’m amazed that insect-eating birds are able to find food. All I’m finding are bitter, toxic ladybugs and spit-covered froghoppers.

But even if I can’t find them, the sagebrush community supports a large diversity of insects. In an Oregon study, researchers documented 168 species of invertebrates on big sagebrush. Instead of doing a visual search, they resorted to a more disruptive technique. They collected entire sagebrush bushes in plastic bags, cutting them off at the base. Then they shook all of the invertebrates off and spent hours in front of a microscope, separating arthropods from leaves and debris. 

Thanks to this study, we can get some idea of what might be hiding here today, well-camouflaged and out of sight. In the Oregon community, the researchers found a whopping 29 species of predacious beetles. There were 14 species of spiders and five species of tiny moths. There were several species of plant bugs (family Miridae) and a wide variety of other true bugs, including both predatory species and sap-feeders.

Nine-spots and ants

This morning’s ladybug tally is getting to be impressive. I’ve counted 92 transverse ladybugs and 50 seven-spots. This is interesting. Unlike in Alberta, where transverse ladybugs have declined to the point of rarity, here they’re still outnumbering the introduced seven-spot by almost two to one.

Once in a while, I also notice another native ladybug. This species, which shows a prominent black line where the wing covers meet, is pretty special. It’s the nine-spot ladybug (Coccinella novemnotata). Once common across much of North America, it has declined so drastically that it has disappeared entirely from many areas. Over the past two years that I’ve been watching insects around Helena, though, I’ve continued to find nine-spots here. In my experience, they’re nowhere near as common as the transverse or the seven-spot. Nevertheless, today I’ve found six of them among the sagebrush.

According to naturalist and ladybug aficionado James Bailey, this is one of the only areas in the United States where it’s still possible to find this species routinely. The story of the nine-spot is a classic example of why it’s important to pay attention to insects. If we don’t, we may not even notice when they disappear. Until two years ago, I didn’t even know that we had multiple species of ladybugs around us. Now, knowing I live among one of the last refuges of the nine-spot, I get excited when I see them.

I’ve mostly been looking for insects on the sagebrush itself this morning, but I can’t help noticing the ants crawling across the ground. These insects are so conspicuous that even I can spot them easily. Do birds eat them?

Yes! For the ground-foraging sage thrasher, it turns out, ants are a significant part of the diet. Vesper sparrows and Brewer’s sparrows have been documented catching ants, too. They may be crunchy and acidic, but at least they’re food!

It’s subtle

It’s getting hot now as the sun nears its zenith. The morning ocean of song has faded. A few Brewer’s sparrows are still singing their short songs nearby, and a club-horned grasshopper (Aeropedellus clavatus) buzzes his wings, sounding like a miniature rattlesnake.

I still haven’t found any nests. But there are so many birds on territory here, especially Brewer’s sparrows, that I’ve probably walked right past a dozen of them this morning.

I look to the south, where the mountains recede into the distance like hazy blue mirages. A breeze has begun. If it picks up, the bitterroot seeds will be dispersing today. The sagebrush shoots quiver in the wind, releasing their pungent smell.

From a distance, the sagebrush rangeland might look lifeless. And even sitting among it at midday, it’s subtle. You have to look closely to see the abundance of ladybugs, the spitting froghoppers, and the jackrabbit resting in the shade. And you might need a Brewer’s sparrow’s eyes to spot the plant bugs and caterpillars that live here, or the bird nests among the branches.

But come back at sunrise, when the birds are all singing, and it’s not hard to tell. This place is full of life. 

Further Reading

Billerman, S.M., Keeney, B.K., Rodewald, P.G., & Schulenberg, T.S. (editors). (2022). Birds of the world. Ithaca, NY: Cornell Laboratory of Ornithology. https://birdsoftheworld.org/bow/home.

Marks, J.S., Hendricks, P., & Casey, D. (2016). Birds of Montana. Arrington, VA: Buteo Books.

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