This story is the second in a series about Lake Helena and getting to know a place in nature over time. If you haven’t heard last month’s installment, you can start there… or just jump in here!
It’s a night in late June at a cattail marsh along Montana’s Rocky Mountain Front. The sun set more than an hour ago, and the pale, peachy afterglow has faded to blue over the backbone of the mountains. The marsh and the dark sky above it are filled with the calls and strange winnowing sounds of a dozen Wilson’s snipes (Gallinago delicata). And then, from somewhere deep in the marsh, we hear it again, that strange, deep gulping sound, wump–CATchum! wump–CATchum!: the distinctive call of an American bittern (Botaurus lentiginosus).
The American bittern is a secretive heron of dense marshes, uncommonly observed in Montana, and this is the first time that anyone has reported one in this marsh. We hear the bittern calling for roughly half an hour as the sun’s last glow fades away. The next morning we hear it once again in the pre-dawn hours, starting up around 4:20 am and continuing for roughly 40 minutes. Before sunrise arrives, though, it’s become silent, a ghost of a bird hiding in the wetland.
Bitterns at Lake Helena?
If a bittern is living here among these cattails, I ask myself, why not at Lake Helena, 64 miles away? The cattail marshes are even more extensive there. And so, four days later, I arrive at Lake Helena at 4:00 am to listen for bitterns.
It’s a chilly, still morning with skeins of mist rising from the lake. I’m standing in waders at the edge of the cattail marsh, cupping my hands over my ears and listening intently. I can hear the clear wichety wichety wichety of the common yellowthroats (Geothlypis trichas) and the chatter of the marsh wrens (Cistothorus palustris). A Wilson’s snipe winnows in the distance. From time to time, I hear splashes and sounds I don’t recognize from the marsh—but no bittern.
A waning crescent moon is high in the southeastern sky and the mountains are black silhouettes in the distance. I’ve listened for an hour now—still no bittern. I’m getting cold. If a bittern was calling, I’m pretty sure I would have heard it. Later, I read that bitterns most often call early in the breeding season. Are there bitterns hiding in this marsh, silent now at the end of June?
July in the marsh
I return to Lake Helena a week and a half later by kayak, arriving before sunrise on July 12. As I drift slowly through the morning darkness, I’m greeted by a cacophony in the marsh. It’s a roaring buzz, notable from hundreds of yards away. It sounds like the cattails are hosting a convention of miniature chainsaws. But as I get closer, what I find isn’t what I had been expecting, a conglomeration of red-winged blackbirds (Agelaius phoeniceus) or marsh wrens. Instead, it’s a massive group of bank swallows (Riparia riparia), easily a hundred of them, perhaps several times that many.
Immediately I have a suspicion about what I’m seeing. A nearby bank swallow colony has fledged, I think, and the year’s profusion of fledglings have moved on from the vertical earth bank where they spent the first three or four weeks of their life. As they forage and get ready for migration, the marsh is a safe haven for them to stop and roost for the night.
Swallows and nighthawks
The pre-dawn sky is pinkish-gray with haze from the Horse Gulch Fire, which started a few days ago in the mountains to the east and has already grown to over 7500 acres. Suddenly, at 5:27 am, the bank swallow flock erupts from the marsh without warning. A swirling cloud of noisy swallows circles over my kayak just long enough for me to snap a photo and estimate that there are at least 250 of them. And then they’re gone, scattering over the lake.
As I continue to drift slowly onwards at the edge of the marsh, I think about all of the stories of the birds and other animals that use this place throughout the year. I wonder how many of these stories I haven’t even imagined. On June 19, 2023, Logan Kahle was at Lake Helena in the evening and observed an astounding 680 common nighthawks (Chordeiles minor) flying over the water, where they were presumably foraging.
“This was a bare minimum estimate, made in a single scan counting by 20s,” he wrote. “I have viewed many amazing nighthawk spectacles over reservoirs in the Great Basin, but this may have been the craziest.”
Marsh wrens and marbled godwits
Presumably Logan had no idea that evening that he would see such a massive group of nighthawks over the lake. Nor did I set out this morning with any inkling that there would be hundreds of bank swallows roosting in the marsh. Often, the most amazing moments in nature just happen, unexpected.
As the sun rises smoky orange over the mountains, I watch a group of three juvenile marsh wrens who give high-pitched begging calls from the edge of the wetland. They still have tufts of downy feathers on their heads, giving me the impression that they only recently got up out of bed and didn’t comb themselves. One of their parents is working overtime to stuff them with insects, hunting diligently for prey among the mud at the edge of the cattail forest.
At the Prickly Pear Creek delta, the swamp verbena (Verbena hastata) is blooming, rich purple spikes against the green of the marsh. A flock of marbled godwits (Limosa fedoa) is circling low over the sandbar, calling. Finally they land there, gull-sized shorebirds with gently swooping, pale orange bills. They dip their bills in the shallow water and tilt their heads up, drinking.
Hot morning at the delta
The morning sun is fierce now, its intensity increased by the water’s reflection. Most of the shorebirds at the delta today are species that nest here: spotted sandpipers (Actitis macularius), killdeer (Charadrius vociferus), and dozens of Wilson’s phalaropes (Phalaropus tricolor). An impressive flock of 70 American avocets (Recurvirostra americana) flies over but doesn’t land.
But even though “summer” only began a few weeks ago on the human calendar, and the May shorebirds that used these sandbars in their northbound migration towards the Arctic are still a recent memory, the mosaic is already shifting. The marbled godwits—shorebirds which breed in Montana but not, as far as I know, in this urbanized valley—are one of the first hints that fall shorebird migration is already starting. But they’re not alone.
Fall shorebird migration
As the morning heats up and the roar of Helena Valley traffic echoes through the soundscape, punctuated by the sounds of red-winged blackbirds and a few other species, the shallow water at the delta is full of foraging shorebirds. Here, alongside the Wilson’s phalaropes, I count nine long-billed dowitchers (Limnodromus scolopaceus) and four western sandpipers (Calidris mauri).
With these two species, there’s no doubt that these birds are already migrating south. Both breed roughly 2000 miles to the northwest, where wet tundra meets the Arctic Ocean. After a compressed nesting season, by now the adults have already begun their fall migration. The juveniles will wait longer—often another month or more—before they too head south, somehow finding their way across the continent to their wintering grounds without the assistance of their parents. Some western sandpipers will spend the winter as far south as the coast of Peru.
Noticing the flies
Past the delta with its shorebirds and its usual group of American white pelicans (Pelecanus erythrorhynchos), I decide to give myself time to slow down and notice some more of the life in this place. There are some flies buzzing along a band of sandbar willows (Salix exigua) that divides the lake from part of the marsh as I record a Virginia rail (Rallus limicola) making short, staccato calls from the wetland. Among the incredible diversity of flies in the world, I have no idea what these ones might be, nor do I try to catch one to observe it more closely and find out.
This patch of marsh is dominated by bur-reed (Sparganium sp.), an expanse of bright green spears pointing skyward, and on the bur-reed flowers I notice some other flies. These ones are bronze-colored with striking yellow bands on the abdomen, suggesting to me that they’re a species of hover fly (family Syrphidae). The flies take off before I can get a photo, but not before I notice that they’re only landing on the small, bright yellow clusters of male bur-reed flowers, which are positioned above the larger, snow-white spheres of female flowers. The hover flies must be finding pollen to feed on, I suspect.
Mudflats in miniature
The morning is getting hotter, and I’m almost ready to turn back. But I paddle just a little bit farther first and stop to photograph the swamp verbena. It’s flowering abundantly here at the edge between lake and marsh, just as it was at the delta. A viceroy (Limenitis archippus), a beautiful monarch-mimicking butterfly whose larvae probably developed on the nearby sandbar willows, is perching on a swamp verbena stem. A second viceroy lands on a mudflat in miniature nearby, flexing its wings. This tiny mudflat has flies, too, but they aren’t the sort that buzz around my microphone to add their voices to a Virginia rail recording. These ones are smaller, delicate, and they glint in the sunlight in tones of metallic copper and green. I suspect they’re some kind of long-legged fly (family Dolichopodidae).
In a special place in nature such as Lake Helena, the learning is endless. Today, it’s been a huge flock of bank swallows roosting in the pre-dawn marsh. It’s been the shifting kaleidoscope of shorebirds using these mudflats and sandbars alongside massive American white pelicans. And pausing to slow down and take a closer look, I’ve seen something similar in miniature: a viceroy perching alongside dozens of tiny long-legged flies, like the insect analogs of pelicans and shorebirds on a mudflat.
Seeing bank swallows, imagining bitterns
I’m left feeling grateful for this habitat that supports so much life, from long-legged flies and bur-reed to bank swallows and the occasional massive concentration of foraging nighthawks. I wonder what Lake Helena will teach me next time. And I keep on imagining American bitterns in the marsh. Perhaps, if I come back on an early summer night next year, I’ll find them here, singing.
In Montana, Montana Audubon coordinates the Important Bird Area program, which includes the Lake Helena Important Bird Area. To find out more about this program and Montana Audubon’s other conservation and citizen science initiatives, visit mtaudubon.org. And if you visit Lake Helena, consider submitting your bird sightings through eBird to contribute to our collective knowledge of this place!
Further reading
Billerman, S.M., Keeney, B.K., Rodewald, P.G. & Schulenberg, T.S. (editors). (2022). Birds of the World. Ithaca, NY: Cornell Lab of Ornithology. https://birdsoftheworld.org/bow/home
Marks, J.S., Hendricks, P., & Casey, D. (2016). Birds of Montana. Arrington, VA: Buteo Books.
Wilson, H. (2012, 5 Aug). Shorebird migration. Maine Birds. Retrieved from https://web.colby.edu/mainebirds/2012/10/21/shorebird-migration/
