January 18, 2023
A waning sliver of moon hangs in a partly cloudy sky this morning. The winter sun lights up the tan grasses, gray cottonwoods, and crusty white patches of snow in Montana’s Helena Valley. The blue curve of mountains that surrounds us remains in shadow. Local birder Stephen Turner and I are driving slowly through the valley, making a 71-mile circuit through cottonwoods, pastures, agricultural fields, and subdivisions. Our goal is straightforward, but by no means simple. We’re trying to count up the overwintering raptors using this valley.
Raptors are hunters. Our smaller birds mostly feed on insects, seeds, and fruits: foods that are often abundant on a local scale. But raptors hunt animals. Depending on the species, their diets may include deer mice, voles, ground squirrels, jackrabbits, trout, suckers, sparrows, and ducks. And for this reason, raptors are relatively rare. Just as there are countless thousands or millions of seeds in the world for every sparrow that exists, there must be many sparrows for every sharp-shinned hawk. For every red-tailed hawk that exists, there are many more voles and deer mice.
For raptors to thrive, their prey must be thriving, too. And so, each red-tailed hawk, bald eagle, or sharp-shinned hawk in the Helena Valley is a sign of health. And when our overwintering raptors diminish, it’s a clue that the landscape is becoming less healthy for all life.
This is the reason for today’s survey. How many raptors are spending the winter in the Helena Valley? And how are their numbers changing, for better or worse, over time?
How are our winter raptors doing?
Today’s survey will take us most of the day. But it’s just one of a whopping 542 routes that volunteer observers are conducting this winter across the northwestern US, from California to Montana.
The project began 18 years ago in Oregon with a simple question: how were the state’s winter raptor populations doing? Jeff Fleischer started coordinating surveys in the winter of 2004, with 79 routes across Oregon that year. Soon, East Cascades Audubon Society began supporting the effort, and it has expanded steadily ever since.
On each route, volunteer observers do a survey once a month between December and February. Some also do surveys in November and March. And once a route is set up, the observer repeats it in the same way on each survey. This makes it possible to compare raptor numbers between months and years.
Montana’s winter raptors
The Montana raptor routes are recent additions to this project. Stephen Turner started this one in November of 2022. And even after just a few months, these surveys are already painting a much more complete picture of our winter raptor populations than casual bird observation ever could.
“If you don’t take the time to survey this stuff thoroughly, you miss a lot,” Stephen tells me. “It’s just so different from just going out to bird.”
“The numbers are much higher than I anticipated,” he continues. “The number of roughies [rough-legged hawks] in the valley is extraordinary.”
In December, Stephen counted 38 rough-legged hawks – an impressive tally in this small valley among the mountains. Red-tailed hawks weren’t as numerous as the Arctic-nesting, cold-adapted rough-legged hawks. Nevertheless, Stephen found over 20 of them in the valley. Based on his November and December sightings, Stephen now expects to count around six to twelve bald eagles on any given survey. And other notable overwintering raptors, present in lower numbers, include prairie falcons, northern harriers, American kestrels, and merlins.
Hunting through crusty snow
So here we are this morning, driving slowly through the valley. As the passenger, I record data and scan for raptors on the right side of the road. Stephen drives, watches for traffic, and counts birds on the left side.
“It really is a lot easier with two people,” Stephen says.
We’re constantly scanning fence posts, power poles, irrigation pivots, and cottonwoods, searching intently for the distant form of a perched raptor. Sometimes we spot one in flight, too, flapping over the fields or circling higher on a thermal of sun-warmed air. We identify what we can with our binoculars, but for more distant birds we pull over and set up Stephen’s spotting scope to confirm.
As we drive along Sierra Road, the snow forms a continuous blanket over the fields. It looks crusty: the sort of snow, shaped by thawing and refreezing, that a hawk might have trouble punching through to catch a subnivean vole or mouse.
“Doesn’t it look like this would be tough for a raptor to work?” Stephen says.
But when we turn onto Floweree Drive, the snow cover gets patchier. And the raptors seem to respond. We find several rough-legged hawks perching on irrigation pivots and power poles. A red-tailed hawk lands briefly on the roof of a newly built house, one of many that are rapidly replacing the Helena Valley’s open spaces. The hawk doesn’t stay long, though, before it lifts back up into the current of a light southwesterly breeze.
From bald eagles to sharp-shinned hawks
We find an adult bald eagle perching in the cottonwoods along Prickly Pear Creek, its white head gleaming when the sun emerges from behind the clouds. Setting up the spotting scope, we identify two more-distant rough-legged hawks, perching on fence posts among the pastures.
Anytime we see a hawk fly, we’re doing our best to track its movements. We want to be careful not to double-count any raptors that move from one area to another during our survey.
It’s when we’re along Helberg Drive, passing slowly by a farmhouse, that the raptor-counting really starts to get busy. Stephen spots a compact, narrow bird perching in a crack willow (Salix fragilis). Its head is small, its tail long and dark-barred. In comparison with the rough-legged hawks we’ve been seeing, it’s tiny. This is a sharp-shinned hawk: an ambush predator that hunts songbirds. And unlike the mammal-eating rough-legged hawks and red-tailed hawks that are so easy to spot perching around the fields, these miniature hawks are truly hard to find. This one must have eaten recently, we think, because it’s perching calmly in the willow. It turns its head and watches us nonchalantly.
Another tiny raptor
As we’re getting ready to move on, I spot a flash of movement on the other side of the truck, along the irrigation ditch. It’s another small raptor, but this one has much pointier wings with tan spots along the primaries. It’s a merlin!
The merlin flies away, screaming in annoyance. It’s unusual to see these birds on the ground. Like sharp-shinned hawks, merlins mostly hunt songbirds. Typically, they perch on power poles or in the tops of trees, searching for prey. Finding a distant bird, a merlin will launch into rapid flight, using speed and topography to ambush its prey.
But this merlin was on the ground. Did she land here just before we startled her, chasing a songbird to the ground? When she takes off, though, she has no prey in her talons. It appears that her morning hunt has not yet been successful.
Rough-legged hawk or red-tailed hawk?
We continue on and scan the fields again. Several bald eagles are perching along a distant fenceline. We count two more rough-legged hawks and then put the scope on another hawk, dark and backlit in a distant tree. With the distance and the bad lighting, this raptor poses a challenge.
Rough-legged hawk or red-tailed hawk? It’s a frequent question in Montana during the winter. Rough-legged hawks typically have a very pale head, an extensive band of dark feathers across the belly, and a white patch at the base of the tail. Red-tailed hawks have a dark head and a narrower band of dark feathers across the breast. Their tails are orange or grayish, without a white patch at the base. But both species are highly variable in their plumage. Some birds of each are “dark morphs”: mostly black-feathered birds without the typical patterns. And some individuals are just so distant that identification can be a struggle.
In cases like these, we also look for some additional clues. Perching rough-legged hawks look pear-shaped. They’re broadest at the belly, with a relatively small head. Red-tailed hawks appear large-headed and broadest at the shoulder. And if it’s possible to get a look at the legs, rough-legged hawks have feathers down to their feet. Red-tails, on the other hand, have bare “shins.”
This distant bird has the broad shoulders and large head of a red-tailed hawk.
As we backtrack past the farmhouse towards the main road, the sharp-shinned hawk is still perching where we first found it in the willow. The merlin has disappeared.
But it’s not our last merlin encounter of the day. Several hours later, we’ve pulled over along Lake Helena Drive to scope another distant hawk when a small shadow dives out of the sky and disappears in the weeds along the far side of the road. We watch expectantly, holding our breath. Soon the small falcon reappears, flying up to a fencepost. And this time the hunter was successful: a vole is dangling from its talons.
By late afternoon, when we finish the survey, our eyes are getting tired. And no wonder: it’s taken us just over eight hours of intensive raptor-searching to complete the route. Compared to Stephen’s December survey, red-tailed hawk numbers have fallen, while rough-legged hawks have remained stable. Today we’ve found 11 red-tailed hawks and 37 rough-legged hawks. We’ve counted 12 bald eagles, three merlins, one sharp-shinned hawk, and one northern harrier.
No survey will find everything that’s present. Today we haven’t found prairie falcons or American kestrels, for example, two uncommon winter raptors that we know birders have seen quite recently in this area. But by repeating these surveys in the same way each time – and by conducting them not just here, but in hundreds of other places across the northwestern United States – a detailed picture of our wintering raptor populations is beginning to emerge.
Raptors under threat
In the Helena Valley, casual observations suggest that we’re losing habitat for raptors – and we’re losing it fast. In just the past five years, new subdivisions have sprawled across what was once farmland along Keir Lane, on the east side of the valley near Spokane Bay. And Stephen, who has been birding the Helena Valley for years, has noticed major changes.
“The subdivision has affected the bigger birds in here,” he tells me.
Bald eagles used to be common in the cottonwoods along Spokane Creek. Rough-legged hawks and red-tailed hawks were frequent along Keir Lane during the winter. And on those rare occasions when a gyrfalcon – an extremely rare winter visitor from the arctic – would show up in the Helena Valley, this was one of the likeliest areas to find it.
“That certainly has changed,” Stephen says.
An important valley
But in spite of the rapid growth of subdivisions and all of the habitat loss that has already occurred, this winter’s raptor surveys are telling us that the Helena Valley is still an important place for overwintering hawks and eagles. This valley supports dozens of rough-legged hawks and red-tailed hawks. The cottonwoods, creeks, and pastures still offer habitat for bald eagles. And, if you get lucky, you might find a merlin hunting for songbirds or voles along a fenceline.
When we go out to count raptors, we’re collecting the information that will allow us to see future trends in our winter populations of hawks and eagles. But it’s about much more than just the numbers. It’s about love for these hunters who share the winter landscape with us. It’s about the grasses and cottonwoods, voles and songbirds, that must thrive to support them. If our raptors can thrive – and if we can watch their populations actually increase over the years, rather than dwindle – then that’s a good sign for the future of life on earth.
Are you interested in volunteering for this project? To find out about winter raptor survey opportunities near you, contact Jeff Fleischer at firstname.lastname@example.org.
East Cascades Audubon Society. (2022). Winter raptor surveys [with links to raptor survey data]. Retrieved from https://www.ecaudubon.org/winter-raptor-survey