Scientists to track climate change for ptarmigans
The Denver Post
ROCKY MOUNTAIN NATIONAL PARK – Amid concerns that climate change will reshape Colorado’s high country, Colorado State University ecologist Greg Wann is on a tough mission: tracking ptarmigans, the elusive mountain birds known for their camouflage.
The conditions he faces trudging after them here at 12,100 feet – sharp rocks, icy wind, a merciless sun – are daunting even during summer.
“It can be difficult getting around,” Wann says. “It’s harder to breathe.”
Cold, snow-packed terrain above tree line, inhospitable to most creatures, is essential for ptarmigans’
Colorado has been a stronghold for the birds until now. But scientists say warming temperatures and decreasing snowpack may mean trouble.
Wann plays the crucial role in a federal government-backed effort to verify impacts and monitor ptarmigans as a possible climate-change sentinel.
“We think ptarmigans are going to have a limited ability to cope with climate change because they are limited to alpine habitats,” said project supervisor Cameron Aldridge, a U.S. Geological Survey scientist and CSU professor. “If something is happening to them, then we should be concerned.”
Wildlife-diversity advocates last month launched a campaign to designate the ptarmigan officially as a threatened species.
A petition filed by the Center for Biological Diversity contends that “warmer winter temperatures, changes in precipitation patterns and the movement of tree line upslope will cause white-tailed ptarmigan habitat to become unsuitable.”
If the U.S. Fish and Wildlife Service agrees, the designation would obligate action to mitigate the threat – including possible limits on carbon-dioxide pollution.
“Americans have committed to preventing the extinction of species like the ptarmigan,” said Noah Greenwald, director of the endangered-species program for the center, which has won protection for more than 360 species.
“This is shrewd, because the ptarmigan is not just a beautiful bird but a bellwether for degradation of the environment we all depend on,” Greenwald said. “Spring snowpacks are already getting smaller and melting earlier, which makes the summer dry season longer and more severe in many areas.
“If this trend continues, it will affect our water supplies as well as have a tremendous impact on our rivers. The ptarmigan’s fate thus is connected to our own.”
Ptarmigans have adapted to thrive in Colorado’s treeless alpine terrain. They’re famous for befuddling hunters and hikers with their cryptic coloration.
When approached, ptarmigans freeze instead of flushing. Around this time of year, they begin to replace their mottled summer brown-black- and-orange plumage that blends them into their granite domain.
They grow brilliant white feathers that render the birds practically invisible against snow.
Their black eyes filter ultraviolet rays. Thickly feathered feet act like snowshoes, allowing ptarmigans to forage without sinking and, on hot days, seek cool refuge in snow fields. They can dig miniature caves in soft snow to evade predators and endure blizzards.
When Wann hikes to find ptarmigans, he lugs a 20-foot pole with a noose on the end and a speaker that broadcasts the cheeps of ptarmigan chicks to lure adult birds.
So far, he has caught and attached color-coded bands to 150 birds. These enable observation from a distance. He’s aiming to catch another 30 before winter.
Prior research indicates climate change already may be affecting the birds. A 2002 study in Rocky Mountain National Park found that rising low temperatures in winter caused ptarmigan populations to decline.
Recent data establish that, compared with the 1970s, ptarmigan eggs are hatching 12 to 15 days earlier in spring, Wann said. That could either help more chicks survive by extending opportunities to forage or hurt survival by exposing more chicks to late snowstorms that prevent them from foraging when they most need nourishment.
The USGS and CSU are running the current investigation. It draws on Colorado Division of Wildlife observations of ptarmigans over 45 years – useful for making comparisons using climate records.
No statewide ptarmigan population estimates exist. State wildlife officials, who once allowed ptarmigan hunting along the Mount Evans Road, have imposed restrictions.
Most ptarmigans live on federal land, much of it protected from development as wilderness.
Staying cool and calm
Last week, nearing the top of Lava Cliffs in Rocky Mountain National Park, Wann spotted movement – a dozen or so foraging ptarmigans.
The birds led him toward a steep talus slope. An eagle swooped over them. They hunkered.
Wann nabbed one, using the pole. Feathers flew. He slid the bird into a cloth sack and clambered to a level patch of grass.
He weighed the bird, then cradled it as he attached the color-coded tracking bands to its leg.
He clipped off one of its toenails, saving a drop of blood in a plastic centrifuge tube for genetic analysis in a lab. Finally, after measuring wing length, he plucked a feather – and released the bird.
Some fly off in a flurry of flapping. But this one, a male, simply stood and walked away slowly.
“I love the way they look. I love the habitat they are in,” Wann said. “I love their calm disposition.”