Migratory Mysteries

Toenail clippings and feathers from song sparrows may help an Ashland researcher figure out where the common but mysterious little birds spend their winters and summers.

The same research methods could help untangle the migratory habits of other bird species that frequent the Rogue Valley.

Last spring, researcher Barbara Massey got help from Klamath Bird Observatory staff members to trap song sparrows in soft mist nests. They weighed and measured each bird, banded it, plucked out a feather and clipped a toenail.

The toenails and feathers were sent to a Canadian lab that can measure hydrogen levels in the tissues. With only a few labs in North America able to do that type of analysis, Massey is still awaiting the results.

She explained that birds pick up different hydrogen levels in their tissues based on where they are living. Researchers have developed a map that shows hydrogen level variations from Florida north into Canada. Because of molt timing, feather hydrogen levels reveal where song sparrows spend their summers. Clipping a slow-growing toenail in the spring and then analyzing its hydrogen levels reveals where the sparrow was wintering a few months ago, Massey said.

Song sparrows travel into the mountains surrounding the Rogue Valley to breed and raise their young. What's not known is whether they are "altitudinal migrants" that winter in the valley and then fly into the mountains come spring, or if they are long-distance migrants that have wintered in southern locales. "It's something that's being investigated. It is very challenging and complicated," Massey said.

Some song sparrows don't travel at all, but instead stay in the valley year-round, she said.

Massey said she hopes to expand the research to other bird species in the future, such as dark-eyed juncos.

The birds with black heads, tan bodies and white underbellies spend their summers in parts unknown, then pop back up in the Rogue Valley in the fall. They are common visitors at bird feeding stations throughout the winter, where they congregate in groups, flitting away with a flash of white tail feathers at any disturbance.

"There's a big question about the juncos," Massey said.

Juncos that winter down in the Rogue Valley may be flying into the surrounding mountains in the spring, or they may be traveling into mountains farther to the north. To complicate matters, it's possible that some groups of juncos use the valley and local mountains, while different groups use the valley but then fly away to northern mountains, Massey said.

Using toenail and feather hydrogen levels to track bird migration may be the best option for solving these puzzles, since they hold records of both a bird's summer and winter whereabouts. The odds are extremely low that a bird banded in a summer location will be recaptured in its winter location and have its band checked, Massey said.

Other researchers are using hydrogen levels to track bird migrations. They are even putting the information to use to try and prevent bird collisions with airplanes, cell phone towers, wind turbines and oil rigs.

In 2009, scientists determined that a flock of Canada geese that hit a passenger jet soon after take-off — forcing its much-publicized emergency landing on the Hudson River — was a migratory flock, not a resident flock. Killing or chasing away resident Canada geese at New York's LaGuardia Airport, where the plane took off, would not have prevented that collision, according to an article in ScienceDaily, a website featuring research news.

Staff writer Vickie Aldous can be reached at 541-479-8199 or vlaldous@yahoo.com.

Share This Story