December 30, 2022

The nest sits in the middle of the hawthorn in front of us, silent and inscrutable. We contemplate it, tucked securely among thorny branches, at the edge of a frozen slough near the Bitterroot River. Perhaps it contemplates us, too. It’s a flat, mossy cup, larger than my two fists. Our question today is simple enough: whose nest is this? But if we hope to find an answer, we’ll have to use all our powers of observation and imagination.

Fellow naturalist Louise Weaver and I are at Maclay Flat today, a popular natural area near Missoula, Montana. The Bitterroot River, Nstetčcx͏ʷétkʷ in Salish, flows past us. Across the river from us is Smlk̓͏ʷsšná, McCauley Butte, and just upstream are the Fort Missoula Ponds. Like those ponds, Maclay Flat is a well-known spot for finding a diversity of birds. And we’re here on this blustery winter day, carrying the Peterson Field Guide to North American Bird Nests, hoping to get better at one form of naturalist sleuthing: winter nest identification.

Nests in winter provide an interesting conundrum. Among the leafless shrubs along the river, they’re easier to find now than during the summer. And we don’t have to worry about disturbing breeding birds or drawing in predators, as we would if we found an active nest in the breeding season. But by the same token, the bird that built it is long-gone now. The nest itself has weathered months of wind, snow, and rain, beginning the slow process of falling apart. To match a winter nest with the bird that built it is, needless to say, not an easy task.

Observing the nest

We start by paying close attention to this mossy cup and its surroundings. It’s about a foot above eye level, near the middle of this thorny hawthorn (Crataegus sp.) – just high enough that neither of us can see inside. At the base of the nest, I can see some strips of fine, fibrous inner bark from an aspen or a cottonwood. The bark is jumbled together with fine, dead grasses and a few old pine needles, black-spotted with decay. Above this base, the majority of the nest cup has been built of mosses: long, brown and gold-green strands of a pleurocarpous species. 

What about the inside? Although we can’t see it directly, I manage to get a glimpse of the inner nest by holding my phone over my head and blindly taking a picture. Mosses feature prominently here, too, along with a few more strips of inner bark and some fine, unidentifiable bits of plant matter. We look for a layer of mud, a notable feature in the nests of some species. None is apparent from our limited, ground-based view.

Listing the suspects

Who built it? Looking at the eBird list of the 192 bird species that have been documented here at Maclay Flat, we can start by ruling out a lot of them. Clearly this nest doesn’t belong to a ground-nesting duck or grouse. It’s too small for any of our raptors. And it can’t belong to a woodpecker, chickadee, or tree swallow: these birds nest in tree cavities. Meanwhile, it’s too large for a sparrow, warbler, or vireo. It’s clearly not the distinctive “hanging sock” nest of an oriole. So which options does that leave?

We come up with a short list of possible candidates to check. Could it be a Steller’s jay? That seems unlikely, since they’re rarely seen here in the summer. American robin? The size seems about right, but robins line their nests with a layer of mud. What else might it be? We add black-headed grosbeak, eastern kingbird, red-winged blackbird, and gray catbird to our list of “suspects.” And what about a Swainson’s thrush?

Robins, Swainson’s thrushes, and catbirds

It’s time to dig into the Peterson guide. I start by looking at the entry on American robin nests. If this is a robin nest, it’s certainly different from those I’ve noticed in the past, which seem to emphasize grasses instead of mosses in their construction. But the Peterson guide does list mosses among the materials robins will use. Once again, robins incorporate a layer of mud into their nests – something we weren’t able to see in this one – but the mud can be hidden by a lining of fine grasses. So could this be an unusual robin’s nest? Possibly.

Next I read up on Swainson’s thrushes. The two nest photos in the Peterson guide seem promising, showing very mossy structures. According to the guide, Swainson’s thrushes typically build their nests in “dense deciduous shrubs or conifer saplings.” That matches. And they use different nesting materials in different regions, with grasses, mosses, and twigs among the common choices. Their nests are also considerably larger than I would have guessed, the size range overlapping substantially with American robins. So a Swainson’s thrush seems like a promising possibility.

What about a gray catbird? These secretive thicket birds build nests with a thick outer layer of twigs or leaves. That doesn’t seem to match our nest. I tentatively eliminate gray catbird from our list.

Blackbirds, grosbeaks, and kingbirds

Red-winged blackbirds build neatly woven nests out of grasses, cattails, and other long fibers. They often nest in marshes, but it would certainly be possible to find one of their nests in a riverside thicket like this one. The neatly woven structure seems like a clear “no,” though. We can remove red-winged blackbird from our list.

How about a black-headed grosbeak? The height and nest placement is right for this species, but the nest itself isn’t. The Peterson guide describes black-headed grosbeak nests as “loose” and “thinly built,” going on to say that the “eggs are often visible through the nest bottom.” This isn’t a black-headed grosbeak nest.

Finally, I read up on eastern kingbirds. These birds build their nests “often on a horizontal limb, well away from [the] trunk.” These nests are surprisingly large considering the size of the bird, with a “roughly but well-built exterior.” Eastern kingbirds can use a wide range of materials for their nests, including mosses. This species seems like another possible match for our nest. The description of nest construction doesn’t quite seem to match, though. Neither does the propensity for building on a horizontal branch instead of a crotch in the middle of a shrub. But in spite of these slight inconsistencies, I don’t think we can definitively rule out a kingbird.

Whose nest was it?

So did this nest belong to a kingbird, a robin, or a Swainson’s thrush? Or perhaps some other species entirely? In the end, we can’t be sure. But getting a definite answer wasn’t the point of today’s foray. The point was to be curious, to remember the summer world of the birds here, and to see how much we could learn from one silent, mossy nest.

In the absence of a solid answer, I like to imagine that a Swainson’s thrush built this nest. During the summer, this place must have felt completely different. This house of moss and tree bark would have been well-hidden among the hawthorn leaves. Four brown-spotted eggs would have been well-camouflaged among the dappled light filtering down to this mossy cup. And above the nest, within the rustling of the cottonwood canopy, perhaps the song of a Swainson’s thrush floated down.

Do you have ideas about this nest? Have you found a Swainson’s thrush nest before? Or do you think some other species built this one? Leave a comment and let me know!

Further reading

McFarland, C., Monjello, M., & Moskowitz, D. (2021). Peterson field guide to North American bird nests. New York, NY: Houghton Mifflin Harcourt.

Séliš-Ql̓ispé Culture Committee. (2019). Nɫʔay, place of the small bull trout. The Missoula area and the Séliš and Ql̓ispé people. Retrieved from https://plateauportal.libraries.wsu.edu/system/files/atoms/file/2019-05-28%20N%C9%AB%CA%94ay%20Missoula%20Valley%20sign.pdf

The post A mossy mystery nest in the hawthorn appeared first on Wild With Nature.

December 7, 2022

When it comes to birds around Missoula, Montana, the Fort Missoula Ponds have a reputation. 

“When you fly over Missoula, you can see these really large bodies of water,” says Jim Brown. 

Once the site of a gravel quarry, the ponds have become a magnet for ducks, shorebirds, and many other creatures. 

In the winter, when the ponds are frozen, the bird activity gets much quieter, just as it does anywhere in Montana. Nevertheless, seven of us have shown up on this snowy afternoon for a bird survey, led by Jim Brown of Five Valleys Audubon Society. It’s a chance to see what’s out here in the cold – and to remember all of the creatures that will be returning in the spring.

We’re just getting started when we spot a red-tailed hawk gliding over the snow-covered grasses. It flares its wings and plunges, landing in the snow. A few seconds later, the hawk is airborne again.

“He’s got something!” Cindy Swidler exclaims. Sure enough, we can see a small rodent – perhaps a vole – in the hawk’s beak. The red-tail flaps back to a ponderosa pine, landing in the top to eat its catch.

From Smlk̓͏ʷsšná to Place of the Killers

Just beyond the pine where the red-tail has landed is the hill known in Salish as Smlk̓͏ʷsšná, a billion-year old block of quartzites and argillites rising sharply above the Bitterroot River. More recently, settlers gave the hill its English name, McCauley Butte. Across from us to the east, on the opposite side of the ponds, is Fort Missoula itself. The Fort, established in 1877, is a newcomer on this landscape compared to Smlk̓͏ʷsšná Butte. But it, too, has a name in Salish. The Fort is known as Sx͏ʷplstwé, “Place of the Killers.” It’s a reminder that Missoula rests on Salish land – land that was taken by military force, not given freely.

And between the Place of the Killers and the striking hill known as Smlk̓͏ʷsšná or McCauley Butte, nestled against the Bitterroot River, are the Fort Missoula Ponds. These two large ponds, ringed with sandbar willows (Salix exigua) and black cottonwoods (Populus balsamifera), are more recent additions to the landscape, the aftermath of a gravel-quarrying operation that mined the river rocks from this area. 

The property known as the Fort Missoula Ponds consists of 86 acres, a mixture of open water and reclaimed grassland. In 2020, the City of Missoula took ownership of the site. For now, the area remains surrounded by a fence and closed to the public. In 2023, the City plans to hold a public input process and decide the future management of the site, considering things like wildlife habitat and recreation.

231 bird species

But even before the City acquired the property, it had become well-known among Missoula-area birders that the Fort Missoula Ponds were special. For six years now, birders have been bringing their spotting scopes and observing the wildlife attracted to these ponds, viewing from outside of the fence. Over that time, they’ve reported an astounding 231 bird species here – making this by far the most species-rich site known for birds in all of Missoula County. 

This impressive list is based on observations that local birders have submitted to eBird, a global platform for tracking and sharing bird sightings that is managed by the Cornell Lab of Ornithology. Many of these observations are supported by photos. Nevertheless, the City of Missoula was looking for a more robust, consistent survey of the birds using the Fort Missoula Ponds. Was this site really as amazing for bird habitat as the eBird data seemed to suggest? 

So in spring of 2022, the City gave volunteers from Five Valleys Audubon Society permission to access the area and conduct a series of formal bird surveys. And so far, Jim Brown tells me, the Five Valleys Audubon surveys have matched very well with the eBird data.

“In a way, for the City’s sake, that substantiated the eBird dataset,” says Jim.

A diversity of ducks

Today, following our most recent period of subzero temperatures, the ponds are thoroughly ice-covered. Any ducks that are sticking around the area have shifted to the nearby Bitterroot River. But as soon as the temperatures warm in the spring and open water reappears here, the waterfowl will be back.

“As soon as these ponds open up, there’ll be stuff in them,” Jim tells me. 

The eBird list for the Fort Missoula Ponds includes a whopping 33 species of ducks, geese, and swans that birders have seen here over the past few years. And among them are some notable rarities, including long-tailed ducks and surf scoters.

“These are unusual, ocean-going ducks,” Jim continues. 

Around Missoula, this is one of just a few places that birders have found these rare sea ducks.

Winter at the Fort Missoula Ponds

A few black-billed magpies fly out of the willows, flashing their black and white wings. A northern flicker bobs past in flashes of orange and brown. We can see a few rock pigeons perching on a power pole to the north.

It’s the quiet season out here, for sure – but there’s still activity around us. Two bald eagles fly past, an adult and an immature. They seem to be having an argument, diving at each other in midair with their talons extended. They sweep northward in their silent dispute, skimming across a panorama of snowy blue mountains.

The ponds froze fast this year.

“It got cold all of a sudden,” says Jean Duncan.

The cold came so fast, in fact, that a western grebe got stuck in the ice, deprived of the long runway of open water that a grebe needs for takeoff. Last week, the Five Valleys Audubon birding team found it trapped in the ice. But then it disappeared – and today, there’s no sign of it. The group speculates that a bald eagle came in and scavenged the unfortunate grebe.

Along the river

Now we’re past the frozen ponds and approaching the Bitterroot River, flowing tranquilly past the cottonwoods that line both banks. The Salish word for the river is Nstetčcx͏ʷétkʷ, which translates as “Red-osier Dogwood Waters.” And indeed, there are many red-osier dogwoods (Cornus sericea) growing among the cottonwoods here, along with wild rose, hawthorns, and more willows.

Cindy Swidler tells me that farther downstream, there’s a great blue heron rookery in the cottonwoods. Heron rookeries are an incredible sight to behold. To me they look prehistoric, these arrays of massive stick nests high in the trees. During the breeding season, it’s easy to find the impressive gray birds standing or sitting on their nests. 

Don’t get too close, though: heron rookeries are sensitive to disturbance from humans. During the spring and summer, too close of an approach can cause the herons to abandon their nests.

The heron rookery isn’t the only special thing about this river corridor.

“It’s a tremendous area for breeding birds,” Cindy says. “Tremendous.”

Based on the eBird data, just a few of the summer birds commonly found at the Fort Missoula Ponds include calliope hummingbirds, spotted sandpipers, and red-naped sapsuckers. There are gray catbirds, warbling vireos, and eastern kingbirds. The grassland supports western meadowlarks, vesper sparrows, Savannah sparrows, and western bluebirds. It’s a bewildering diversity, far too much to list here – much more than the handful of birds we’re finding on this wintry day.

Life among the cottonwoods

Now we’ve stopped to look at a cottonwood where beavers have been gnawing on the trunk. We can tell the chewing is recent, because there are fresh wood chips on top of the snow. An old Bullock’s oriole nest is hanging from a limb – the sign of yet another of those summer birds that Cindy was talking about.

Kristi DuBois points out another cottonwood, the top of this one dead and broken. 

“Nice woodpecker holes up there,” she comments.

Cottonwoods are very important trees for wildlife, hosting not only woodpeckers and many other cavity-nesters, but also western wood-pewees, least flycatchers, red-eyed vireos, and an incredible diversity of insects. 

We continue farther along the cottonwoods, passing a flock of black-capped chickadees hunting for food in the willows. A narrow wildlife path leads us down to the edge of the river. The water slips past smoothly, and here the winter birding starts to get a bit busier. A belted kingfisher chatters in the distance. Then we notice three common mergansers, drifting near a gravel bar. Eventually they climb out of the water onto a small island. The mergansers mostly hunt fish, though they may also catch other aquatic creatures such as crayfish and frogs.

“They seem to make little runs off of that spit and come back to it,” Jim observes.

A mallard hen paddles amiably against the current nearby. Then we spot three common goldeneyes, diving actively near the mergansers.

Managing for wildlife

The river – and the cottonwoods and red-osier dogwoods along it – make the area around the Fort Missoula Ponds extra-special. More than just an isolated block of habitat, this area is part of an important wildlife corridor that follows the river. Upstream is land owned by the University of Montana. Downstream is a minimally-developed parcel which hosts Learning with Meaning, an educational organization. Beyond that, a conservation easement protects much of McCauley Butte itself. And across the river, just a bit farther downstream, is Maclay Flat, a large public natural area managed by the US Forest Service.

The Fort Missoula Ponds provide a key link in this habitat corridor. 

“It’s a great opportunity to restore an old gravel mine into a productive natural area,” Jim says.

Management for wildlife habitat and recreation can be a tricky balance. 

“There are a lot of people, understandably, that want to come enjoy a pond,” Jim says. 

But in the case of a site that’s so important for birds, Jim maintains, finding this balance is critical. Too much human traffic can drive the birds away. That’s especially true during the warmer months, when the ice has melted from the ponds. Too much love from pedestrians isn’t the only worry: off-leash dogs during the warm season would be especially damaging for wildlife.

“A lot of these migrants that come through here are very sensitive to human disturbance. If you don’t manage that, you’re going to lose them,” says Jim.

Migration at the Fort Missoula Ponds

The diversity of spring and fall migrants that use the Fort Missoula Ponds is especially stunning. Several years, hundreds of snow geese have stopped here. Five species of grebes pass through here commonly, and sometimes birders have spotted a less-common sixth species, the Clark’s grebe. The shorebird diversity is impressive: 18 species have turned up here. And when it comes to warblers, migration brings not just common species such as yellow-rumped and Wilson’s warblers, but also occasional, notable rarities like a black-throated gray and a magnolia warbler. 

Jim explains that Five Valleys Audubon Society hopes that the City will be able to develop public trails in some areas here. Wildlife viewing blinds along the trails would allow the community to see this amazing diversity of birds up-close, while minimizing disturbance to the birds. At the same time, for the sake of the wildlife, the Audubon chapter advocates for maintaining some completely undeveloped areas to serve as safe spaces for this incredible diversity of feathered visitors.

A late migrant

We’re getting ready to leave the river corridor when Jillian Leblow spots a flash of movement as a small songbird flies into the top of a willow. It immediately disappears from sight. We wait several minutes, but it’s as if the bird has vanished entirely.

From the split-second glimpse that I got of its flight, I think it was probably a chickadee. Someone else in our group expresses the same opinion. But Jillian is patient. The rest of us have just about given up when she spots it again, very backlit in the top of the willow.

“I think it’s a ruby-crowned kinglet!” she exclaims.

Ruby-crowned kinglets are insect-eaters that typically migrate to the southern U.S. and Mexico for the winter. After weeks of intense cold, it would be truly surprising to find one in Missoula still at this season. Jillian and I race off towards the willow, changing our angle so the sun isn’t shining directly into our eyes. As we approach, I hear a quick, harsh chatter – the call of a ruby-crowned kinglet! The bird flies into a nearby hawthorn and we both get a definitive look at its white wingbars, olive-gray body, and pointy bill for insect-hunting. A ruby-crowned kinglet indeed!

“I always feel like that’s the benefit of waiting,” Jillian says. “Was it a chickadee?”

In this case, it was something far more unusual.

Herons and American tree sparrows

As we walk back towards the cars, two great blue herons flush from the ice of the ponds. Even in their opaque winter stillness, the Fort Missoula Ponds are attracting birds. Are these two herons some of the same individuals that nest in the rookery here in the summer?

We get back to our cars: today’s survey is over. But then I notice that the weedy mound of dirt near our parking area seems to be crawling. Among the scraggly kochia (Kochia scoparia) that covers this mound, a flock of birds are feeding. They’re American tree sparrows, crisp and beautiful in the stark elegance of their plumage. And they’re giving us an excellent look.

Here we are, seven birders, standing awestruck in an unmarked parking lot at the edge of Missoula. The tree sparrows are busy and unafraid, picking seeds from the ground and from the tops of the kochia plants. One comes even closer to us and works on the crested wheatgrass seedheads, flying at them and bending them down to the snow. There, it proceeds to peck away, stocking up on calories for the cold nights ahead.

Biodiversity at the edge of Missoula

This has been a relatively quiet afternoon for birds – the sort of quiet that we can expect during the cold winter season. But even so, it’s clear that the Fort Missoula Ponds are one of Missoula’s special places for wildlife and nature. We’ve gotten to see tree sparrows gathering seeds, a red-tailed hawk hunting voles or mice, and great blue herons flying up from the frozen ponds. We’ve seen a beautiful cottonwood stand with woodpecker nest holes and at least one oriole nest, hints of this place’s summer abundance. And I’ve gotten to make friends with a remarkable group of Five Valleys Audubon Society volunteers – people who care about this place and can see its potential for wildlife and for the community in the years to come.

In the grand sweep of time, the Fort Missoula Ponds are very recent happenings on this landscape. Sandwiched between the ancient hill known as Smlk̓͏ʷsšná and Sx͏ʷplstwé, the Place of the Killers, these ponds are younger even than Fort Missoula.

But even in the relatively short time of their existence, the birds have found them and responded. The Fort Missoula Ponds area has become a biodiversity hotspot at the edge of Missoula. In a time when, all around the world, wildlife habitat is disappearing rapidly, these ponds provide a ray of hope. And with thoughtful management, they will become even more important for wildlife and the community in the years ahead.

For updates on the birds at the Fort Missoula Ponds, or to volunteer with future bird surveys, get in touch with Five Valleys Audubon Society.

Further reading

Lewis, R.S. (1998). Preliminary geologic map of the Montana part of the Missoula West 30’ x 60’ quadrangle. Montana Bureau of Mines and Geology Open-File Report 373, 1 sheet, scale 1:100,000. Retrieved from https://mbmg.mtech.edu/mbmgcat/public/ListCitation.asp?pub_id=11220&

Murdock, Joshua. (2022, 6 Jul). Birders eye prime habitat at Missoula’s Knife River Ponds. The Missoulian. Retrieved from https://missoulian.com/news/local/birders-eye-prime-habitat-at-missoulas-knife-river-ponds/article_df543aec-64c4-5a0b-bcee-61e2bdf8c8a8.html

Séliš-Ql̓ispé Culture Committee. (2019). Nɫʔay, place of the small bull trout. The Missoula area and the Séliš and Ql̓ispé people. Retrieved from https://plateauportal.libraries.wsu.edu/system/files/atoms/file/2019-05-28%20N%C9%AB%CA%94ay%20Missoula%20Valley%20sign.pdf

The post The Fort Missoula Ponds: a hotspot for biodiversity appeared first on Wild With Nature.