Graduate Student Studies Bighorn Sheep Food in Tetons
As a former paratrooper, Ryan Martin is accustomed to heights.
The wildlife ecologist pursuing a doctorate in Professor Ryan Long’s University of Idaho wildlife lab, often finds himself at elevations much higher than most people commonly experience.
Martin studies bighorn sheep forage in Wyoming’s Tetons, where elevations reach 14,000 feet. He wants to know if the amount and type of forage limits the distribution of bighorns, its nutritional value, and how the sheep survive on available food sources.
“A lot of these sheep once migrated, but they no longer do,” Martin said. “Human activity including rural neighborhoods, sprawl and cross-country skiers on historical sheep range have prevented some herds from migrating in search of seasonal food or less harsh seasonal environmental conditions.”
The solitary, non-migrating populations are stuck in isolated parts of the range, often at high elevations, year-round and must make do with the conditions — cold, wind and snow in winter — and available forage.
Bighorn Nutrition as Limiting Factor
“We’re trying to determine if nutrition is a limiting factor that keeps sheep from doing better in these isolated populations,” Martin said.
The results, combined with a series of other research, could help wildlife biologists understand why bighorn numbers have declined to around 80,000 from 200,000 animals in North America in the late 1800s.
Martin, who joined Long’s lab after earning a bachelor’s in ecology and conservation biology at U of I in Spring ’23, didn’t grow up with ambitions to become a scientist. Instead, he fell into the field in a controlled manner.
“I spent a lot of time outdoors with my dad, we did a lot of bird hunting, mostly ducks,” said Martin, who grew up in a small town north of Wichita, Kansas. “When we were outdoors, my dad taught me attention to detail.”
He learned the common names of plants and what animals ate, and he thought it would be cool to be a wildlife biologist.
It wasn’t until after spending several years in the Army as a parachutist that he felt financially able to attend college. He enrolled in a community college near Fort Bragg, North Carolina, where he studied rare plants and decided to venture west after learning what U of I’s College of Natural Resources offered its students.
As an undergraduate ecology and conservation biology major, he spent a few seasons working as a seasonal wildlife technician joining a group studying bighorn sheep near Asotin, Washington. He also explored mountain lion predation on elk and deer in North Idaho.
“I knew I wanted to go to graduate school because it would lead to a permanent position doing research instead of doing summer field work,” he said.
Finding Winter Forage
Bighorn sheep in the Teton Range quit migrating about 70 years ago. They persisted on the mountain range in the northwest corner of Wyoming near the Idaho border as a resident population. Sheep tracking studies show that the Teton bighorns follow a pattern of abbreviated migration. Instead of moving across their 40-mile range or expanding it, the animals follow an abridged migration that includes traveling approximately six miles with descents of around 2,000 feet depending on food availability. The bighorns often seek out high-elevation, wind swept ridgelines to find winter forage.
“Where I am from, nobody really became a scientist.”
— Ryan Martin, Doctoral Student
Martin is helping identify what sheep eat at certain times, and the habitats that support sheep forage. The research will help scientists understand the benefits of migration and may aid in the conservation of bighorn populations in the face of future migration loss.
Naming the Plants
Martin knows the plants eaten or avoided by ungulates by their taxonomic names.
“It’s just easier to learn the scientific name than familiar names that often change depending on the region,” he said.
His inventory includes Chamaenerion angustifolium, Vaccinium scoparium, Carex geyeri and Achillea millefolium.
Translated, the common names are fireweed, grouseberry, elk sedge and common yarrow. Some plants attract wildlife, and a few varieties attract people.
“Ceanothus velutinus has small, vibrant blooms that look like snow, and it smells like cinnamon,” Martin said. “It’s very pleasant.”
His forage studies in Wyoming’s high mountains are a spinoff of research by the Teton Bighorn Sheep Working Group.
“Much of the impetus for my work stems from the previous work this group has done,” he said.
He heads to the high country when the weather breaks and mountain meadows turn green, and he stays until the skies darken with snow clouds around late September following sheep, learning what they eat, and its nutritional value.
Sheep Nutritional Ecology
“There is a huge interest in bighorn sheep nutritional ecology throughout the West right now,” Long said.
As Wyoming sheep range shrinks, Martin’s research is paramount in identifying the plants the sheep rely upon for food, Long said. He mentored Martin on his senior thesis project on bighorn sheep food.
“Martin was one of very few students who I was confident was ready to go straight into a Ph.D. program,” Long said.
Hailing from the flatlands of middle America surrounded by fields of corn and wheat, where dust from combines can darken the sky in August, Martin is pleased to be working in the clear air near the continent’s tip tops. And he is delighted to be on the research track.
“Where I am from, nobody really became a scientist,” Martin said.
Article by Ralph Bartholdt, University Communications.
Photos by Ryan Martin.
Published in July 2023.