PROSPECT — Mathew Vargas pulls his government pickup to the side of the forest road where the GPS tells him to, cuts the engine and steps out to chronicle one of the more fascinating facets of the High Cascades each spring.
The Oregon Department of Fish and Wildlife biologist is listening for the hoot of a male sooty grouse as it’s laying down the law in this slice of Rogue River-Siskiyou National Forest above Prospect.
The grouse’ low, guttural hoot is telling any female in earshot that he’s the one. Monogamy is no virtue in the upland game-bird world, so he’s constantly swiping right on Bird Tinder while telling males there’s no future for you here.
The deep grunts emanating from a Douglas fir stand tell the story, loud and clear.
“There he is,” Vargas says. “He’s puffing up, acting tough. Chasing the males away.”
State wildlife biologists like Vargas are in the midst of another spring survey for sooty grouse in an effort to better understand what this somewhat rare bird of the woods is up to these days throughout the Cascades.
The annual surveys, conducted since 2012, use the presence of hooting males each spring as an index to the relative health of this large forest bird. A downward trend in populations in Western Oregon have triggered a closer look at these birds, which are still hunted in fall.
The best way to track them, for now, are these surveys to listen for hooting males, attempt to pinpoint their location and determine what forest habitats they are using.
These birds use everything from forest openings to deep, dark old-growth canopies during a life cycle that still has a lot of holes for humans trying to understand them.
“That’s what we’re trying to figure out,” says Mikal Cline, an ODFW biologist who is heading up the sooty grouse survey program. “We’ve been concerned about the trajectory of these birds, and we don’t know a lot about them.”
An Oregon native of conifer forests first documented during the Lewis and Clark Expedition in the early 1800s, sooty grouse were initially lumped with dusky grouse and known as blue grouse for decades.
But in 2006, discoveries of genetic and behavioral differences led scientists to split the two into separate species, now joining ruffed and spruce grouse as native forest grouse in Oregon.
Sooty grouse occupy the coniferous forests of Western Oregon, the eastern slopes of the Cascades, the Blue Mountains of northeastern Oregon, and the Klamath Basin and South Warner Mountains.
“Sooties,” as they are called, are second in size in Oregon only to sage grouse, which pepper the high-desert habitats of Eastern Oregon.
Sooty grouse preferred habitat includes timber edges, open timbered slopes and mountain meadows, often adjacent to springs or other sources of water. They are often associated with berry-producing areas such as chokecherry thickets.
In the spring, they favor open forest habitats where they feed on berries and grasses, and bring bugs back for their young to help with their feather production.
And they don’t flee south in fall like migratory birds. Instead, they travel upward into the thick forest canopy to wait out winter while feeding almost exclusively on pine and fir needles.
They’re big birds, growing up to more than 3 pounds. While rarely seen in spring, they are often spotted in the fall dusting themselves on forest roads.
The spring surveys conducted by Vargas and other ODFW biologists throughout Western Oregon are a study in old-school biology, looking to compare annual snapshots of what appears to be happening in the woods each spring.
Surveyors drive specific forest routes during the same time period each spring, stopping at the exact points each year to listen for three minutes for hooting males during daybreak when they are thought to be their most vocal.
The surveys are not designed to create specific population estimates but to generate a relative year-to-year abundance and population trends. It’s called indexing, and the methodology is a stalwart of fish and field biology in the West.
But Vargas and his ears are about to get a technological upgrade.
ODFW is phasing in the use of acoustic recorders in its grouse surveys, placing computers in the woods to listen for grouse hooting 24/7.
Cline says the acoustics could highlight peak mating season or perhaps even show that males are hooting up mates and warning off competition during full moon nights.
Constant monitoring is bound to provide more information than what Vargas can hear during his three-minute stops.
“It’s a nod to efficiency,” Cline says. “We don’t know because we’re not out there listening at all hours.”
Together, the data could help ODFW discover what forest habitats sooty grouse need, when they need them and what combination of open habitat and thick forest canopies is best for this backwoods hooter.
“Surveys are one thing, and they’re important for indexing the population,” Cline says. “But if you can start relating those trends to variables out there in the environment, we can understand the bird and its trends better.”
Reach Mail Tribune reporter Mark Freeman at 541-776-4470 or email@example.com. Follow him on Twitter at www.twitter.com/MTwriterFreeman.