February 7, 2023
The breeze is barely noticeable among the snow-covered pastures and hayfields near Drummond, Montana, but the clouds high overhead tell a different story, their flowing forms a sign that a strong current is moving over the mountains. Thomas Kallmeyer and I are counting hawks and eagles here today. Like Stephen Turner’s raptor route near Helena, this is part of a multi-state project coordinated by Jeff Fleischer to track overwintering raptor populations. But today we’re faced with a puzzle: why are there so few raptors here?
It hasn’t been a totally birdless day, to be sure. Though we didn’t find any eagles in the cottonwoods along the Clark Fork River, there was a merlin perching on top of a spruce near a cluster of houses. A few miles later, among a rolling expanse of snow-covered pastures, Thomas spotted a prairie falcon, a narrow-bodied brown silhouette on a distant power pole. As we approached the foothills at the edge of the valley, we took a quick break from the raptor search to watch a flock of snow buntings. They were picking up grit from the road and foraging among clumps of horse manure in a pasture, taking off occasionally in a flurry of black and white.
It’s continued like this through the rest of today’s survey. The birds haven’t been completely absent – but they’ve been nowhere near as abundant as we would expect them to be. Every so often, we’ve spotted a rough-legged hawk perching along a field. Here and there, we’ve found a few bald eagles. But for all of the open fields we’ve driven past, the density of raptors has been surprisingly low.
More hawks in Helena
“This is phenomenally quiet,” I comment.
“It is,” Thomas responds. “And I hate to say it, but it’s usually like this.”
Thomas started surveying this route earlier this winter. Just like the route Stephen Turner does near Helena, the plan is to survey it once a month throughout the winter, every year from now on.
The length of these two routes is roughly comparable. But while Helena has experienced an explosion of housing developments in recent years, the Drummond area remains very open: a place of pastures and hayfields, with a scattering of houses and a meandering network of streams. At a glance, the habitat around Drummond looks better for winter raptors than it does around Helena.
But that’s not what we’re finding today. By the end of our survey, we’ve tallied just 17 bald eagles and 12 rough-legged hawks. There have been a few other species represented by one or two individuals. We’ve found only two red-tailed hawks. Northern harriers and American kestrels have been absent.
The bald eagle numbers actually compare favorably with Helena: 17 here today, versus 12 there in January. But everything else has been much sparser, especially the soaring hawks. Around Helena in January, Stephen Turner and I tallied 48 rough-leggeds and red-tails combined. Here, Thomas and I have found only 14 of these hawks. It’s a conspicuous, surprising contrast.
A nagging question
To be sure, even this raptor-sparse day has had its highlights. There was the rippling flock of snow buntings wheeling over the pasture. We’ve seen skeins of mallards, hundreds of them, crossing the sky and landing in the cow pastures. Checking a distant eagle with the spotting scope, we realized there were actually three immature bald eagles in a row, lined up along a high-tension power line.
At one point, we found a golden eagle perching on a snow-free, south-facing knoll in a narrow side valley where the pastures climbed gently up towards the forested mountains. His or her nape shimmered dully in the cloudy afternoon. The eagle stayed there for minutes, perhaps digesting a rodent.
But at the end of the day, the question still remains. Why so few raptors? On a route of similar length, at a similar time of year, we saw considerably less than half the abundance of hawks that Stephen Turner and I saw in the Helena Valley a few weeks before. And this has been Thomas’s experience consistently throughout this winter’s surveys here. Yet the habitat around Drummond appears more intact than the Helena Valley, less dissected by houses and busy roads.
The invisible side of raptor habitat
“It has to come down to food, right?” says Thomas.
When we consider food, we’re thinking about voles and other rodents. Are rodent populations just lower around Drummond than Helena this year? Might we see this pattern flip-flop in some future winter?
Or is there something else at play here, beyond what we can see? Thomas wonders whether people might be poisoning rodents, accidentally poisoning hawks and eagles at the same time.
These are questions that we can’t yet answer. But these differences – lots of raptors in the Helena Valley, low numbers near Drummond this winter – highlight the importance of a regional survey effort like this. Our winter raptor populations are anything but uniform. And if we weren’t looking, we wouldn’t even have a clue.
Bald eagles, hawks, and spring on the way
Slowly but surely, this winter is waning. The sun is getting stronger. Soon, the winter raptor survey season will wrap up. Meanwhile, what lies behind these questions about winter raptor populations, sparse in one area and common in another, will take some time to understand. But eventually, by working with the hundreds of observers who are conducting surveys like this, from northern California to western Montana, I hope that we’ll be able to gain a better understanding of what’s going on with our winter raptors.
Today we saw a bald eagle perching on a massive stick nest in a cottonwood along Flint Creek. For the eagles, the nesting season is already starting. Soon, spring will be showing itself, a little bit more every day. The meadowlarks will return and our winter rough-legged hawks will start soaring north again, migrating towards the summer tundra. But when the cold weather comes again this fall, we’ll be ready, counting hawks and eagles and watching as the next chapter in their overwintering stories unfolds.
To find out about opportunities to conduct raptor surveys near you next winter, contact Jeff Fleischer, firstname.lastname@example.org.