Habitat survey sheds light on survival of mule deer
Huge-eared and inquisitive, mule deer are an iconic species found just about anywhere there's vegetation in the Western U.S.
Mule deer's natural habitat across the West has been substantially altered by agriculture, and in some areas, the species' numbers have declined. In the last few decades, however, many farmers have used federal conservation programs to restore sensitive lands to grass and shrub. Scientists at Washington State University want to know how agriculture and restored fields in southeastern Washington affect mule deer.
Trekking grasslands in southeastern Washington, Rebekah Lumkes, a School of the Environment master's student, and her advisor, Professor Lisa Shipley, study the link between changing habitat and fawning locations—sites where baby fawns are born and cared for by does.
"Mule deer are an indicator species," Lumkes said. "They're sensitive to changes in habitat, especially their cover and forage, that agriculture and development have brought to the West."
In a three‑year study funded by the Washington State Department of Fish and Wildlife, Lumkes is surveying habitat at fawning sites for 30 radio-collared does from Walla Walla to Clarkston, Washington.
"I look at the habitat they're choosing, and especially, where they are giving birth and hiding their fawns," said Lumkes. "Fawn survival is what drives population. If you have a lot of fawns surviving, your population will go up. If a lot are dying, population will go down."
During fawning season, May through July, Lumkes seeks just‑born fawns in the field. In a typical excursion on a cloudy June day, she navigated knee‑high grass in a low canyon splitting wheat fields near Pomeroy.
Lumkes swept her radio antenna back and forth a few times, quickly homing in on the telltale tone. Moments later, a doe, radio collar number 877, bolted from cover and bounded down the gully. Watching closely, Lumkes backtracked to the doe's estimated starting point, then began quartering the area for her fawn, born two nights prior.
Newborn fawns are tiny, weighing only about six pounds. Their spotted coats perfectly camouflage them, and they remain curled and quiet when mom is away. To find them, "you have to be practically on top of them," Lumkes said. "Some days we get skunked. We don't always find them."
When Lumkes locates a fawn site, she measures the height of cover at the site and nearby, notes the types of vegetation, features of the landscape, and takes photos. She'll use that data to get a clearer picture of how land use practices affect where fawns are born and raised.
One of the questions that Lumkes seeks to answer is how much mule deer rely on habitat in the federal Conservation Reserve Program, which sets aside environmentally sensitive lands from farming.
"Do they need these pockets to survive?" she asked. "If so, we could encourage more conservation to make sure there are areas for deer and other species."
"Mulies," Lumkes admitted, are her favorite animal.
"They're a beloved species, an important game animal, and as large herbivores, they play an important role in the ecosystem, linking plants to predators," she said. "What happens to them has a lot of implications for a wide range of wild species, from native plants and insects to many species of birds and mammals."