Wild With Nature

June 13, 2022

Just looking at a Brewer’s sparrow, you wouldn’t know there’s anything special about it. It’s a small bird, gray as dust, well-suited to hide among the gray-green sagebrush where it lives. You might even call it drab. But if you hear a Brewer’s sparrow singing at dawn, perching at the top of the sagebrush, pouring out a chorus of trills and chirps, it’s anything but drab. To me, it’s the voice of the western sage lands.

In the Helena Valley, Brewer’s sparrows are fairly rare. To hear one singing, you have to drive out of the valley, past the Scratchgravel Hills, and stop in the sagebrush flats near Silver City. It’s a well-known spot where birders see them every year. And no wonder – the sagebrush there stretches to the horizon. But in June of 2017, I found a surprise: four Brewer’s sparrows singing in a tiny, 30-acre patch of sagebrush on the other side of the valley.

It was exciting to find these sagebrush specialists in this small habitat fragment, on BLM land near Devil’s Elbow Campground. But in the years since, no one else has reported Brewer’s sparrows here. Time has slipped past, leaving questions unanswered. How did they fare? Was my sighting a fluke? Or do Brewer’s sparrows nest here, unnoticed, every year? I’ve decided it’s time to find out. So today, I’ve come back to Devil’s Elbow.

At the edge of the pines

The air is cool and moist this morning after a brief rain shower. A yellow-rumped warbler is singing repeatedly from the ponderosa pines that grip this rocky hill. This is the low edge of the conifer forest, which runs down the mountains in scraggly strings. Below me, the sagebrush covers the gently sloping bench that extends towards Hauser Lake. I have no idea if I’ll find Brewer’s sparrows here this morning. But whether I do or not, I’m going to take a close look. What’s living on these margins, between the pines and the lake?

The sun is just rising over the eastern ridge. The sky is layered with clouds in dusky shades of gray, blue, and purple. A lone pelican soars over the river, bright white against the cliffs. Two ravens are croaking from the far hillside. The spotted towhees mew from across the water, where the junipers are dark against the wet spring grasses. The lake is a mirror. In the distance, sunlight is catching the fields at the base of the Elkhorn Mountains.

A red crossbill chips crisply nearby. A few Clark’s nutcrackers croak in the distance. Below me, a chipping sparrow is buzzing from the sagebrush. 

Feed me!

I’m standing at the edge between habitats, where the ponderosa pines and Rocky Mountain junipers mix with big sagebrush and bluebunch wheatgrass, heavy with the recent rain. And here, on the margins, is a family of mountain bluebirds. Both adults are working hard this morning, perching on the shrubs and then sailing towards the ground, snatching insect prey. Three hungry juveniles can’t seem to keep quiet. It’s a constant chatter of “feed me”: a trembling pew, pew, pew. Their wings tremble, too, as they follow their parents, begging. 

I can’t tell which insects the parents are finding here this morning, but I’m glad that they are. I notice several narrow-winged white moths flying around. Moths for breakfast? After my experience with aphids earlier this month, I don’t try to sample one.

Nearby, a cedar waxwing is carrying a long, dead grass stem into a juniper clump, building a nest. Cedar waxwings nest late so that the young can take advantage of summer fruit. Two robins zoom past me in a high-speed chase, skimming the tops of the sagebrush. 

Down in the sagebrush, a vesper sparrow is singing, its complex whistles competing with the traffic noise from nearby York Road. Meanwhile, a red crossbill flock is foraging in the pines on this hill. Their quiet tapping, as they force cone scales apart, is occasionally interrupted by insistent begging calls from the streaky gray juveniles. Sometimes the brick-red male gives a few hard chip calls as he stops to feed a pesky fledgling.

Into the sagebrush

I move down into the midst of the sagebrush, soft and gray-green against the mountains. From time to time I catch a waft of its pungent, bitter-herbal smell. Some of it is as high as my head. A very wet transverse ladybug (Coccinella transversoguttata) rests on a leaf near a colony of black aphids. I can hear the trills of chipping sparrows and the whistles of the vesper sparrows. A violet-green swallow darts low overhead, chattering. But no Brewer’s sparrows sing.

I keep walking through the sagebrush, listening carefully, but I don’t hear the cascading buzzes and trills I’m hoping to find. Is it possible that this habitat patch is just too small, too cut off by roads? Was my 2017 observation an anomaly? This spring, new construction is going on just to the north. Was this habitat once suitable, but no longer? 

Size matters

There are roughly 30 acres of gently sloping sagebrush here, bisected by the road to the campground. In a review of Brewer’s sparrow biology, Paula Hansley and Gary Beauvais note that these birds have nested in sagebrush patches as small as 15 acres. But larger patches are more likely to host them, and more likely to have consistent nesting every year. 

Of course, simply whether or not the birds are present is only part of the story. Work in two Wyoming natural gas fields has shown that predators destroy Brewer’s sparrow nests more frequently as the amount of sagebrush within a kilometer (0.6 miles) of the nest drops. So can this 30-acre sagebrush patch ever provide good-quality habitat for Brewer’s sparrows? We don’t know for sure, but the evidence suggests it may not.

This year, at least, the Brewer’s sparrows have all chosen other patches for nesting – hopefully big, healthy patches where their chances for success are high. Will we find them at Devil’s Elbow again in some future year? It remains an open question – and if you do, I’d love to hear about it! And in the meanwhile, the hour is still early. What else is using this habitat today? I continue my walk.

The edge of the rocks

The sun plays tag with the low gray tatters of stratus drifting across the hilltops. The singing in the sagebrush has reached a lull. It’s quiet now except for the occasional buzz of a chipping sparrow and the patient chirping of the spring field crickets (Gryllus veletis). Noises from the road and the campground drift in faintly.

I follow the paved pedestrian trail south, towards Clark’s Bay. The habitat becomes steep and rocky. Blazing star (Mentzelia) rosettes grow scattered on slopes of billion-and-a-half-year-old shale fragments. The sagebrush is sparser here, mixed with lively green clumps of skunkbush sumac (Rhus trilobata) in the draws. A violet-green swallow perches on a mullein stalk, grooming himself. He begins to chirp and flies off.

Even the grasses are different here. Purple threeawn (Aristida purpurea) is growing along the path, while Indian ricegrass (Oryzopsis hymenoides) occupies the slopes. A patch of desert evening-primrose (Oenothera caespitosa) is flowering in the loose shale, low clusters of pink and white just below the bedrock itself.

Safely above me in the rocks, a chipmunk is feeding, front paws clasped together around the food item. The ravens are croaking again, their voices echoing off of the slopes.

A nest in the shale

A violet-green swallow darts into a crevice in the rock and disappears. Where did she go? I shift around for a better view. Near the top of the rock face, there’s a rectangular hole in the shale. And well-hidden, several inches inside, is the swallow. Several other swallows fly past me and perch at the top of the outcrop, chirping loudly. I back up to give them more space.

The female is out of the rock crevice now. I watch her land on the gravel alongside the trail. What is she doing? She lifts off with two dead pieces of grass hanging limply in her beak, circles, and then darts straight into the cavity in the rocks. Nest building! Brewer’s sparrows aren’t nesting here this year, but violet-green swallows certainly are.

Devil’s Elbow in the rain

A steady drizzle begins as I retrace my steps past the skeins of evening-primrose. As I follow the path back along the margin of the sagebrush flats, a chipping sparrow is still snoring his song. The sound of the rain melts into the leaves of the sagebrush, but it hits the asphalt path with a hard tink. A grader is sounding its backup alarm in the construction area to the north. 

The Brewer’s sparrows are not here. Will they be back some year soon, or was 2017 just a fluke? We’ll have to wait, keep listening, and find out. Let me know if you find them here! Even if they do come back to Devil’s Elbow, this patch is so small that the habitat seems marginal for them.

But while the Brewer’s sparrows are raising their chicks in sagebrush patches that stretch to the horizon, these margins between pine forest, sagebrush, and water are still full of life. We have red crossbills, cedar waxwings, mountain bluebirds, and violet-green swallows raising young here. We have desert evening-primrose clinging to the hillsides, chipping sparrows snoring in the sagebrush, and towhees mewing from the undergrowth. People of all mobility levels can walk these paved trails. I didn’t find what I was looking for today. But I’m glad that all of this is here.