STEVENS PASS — Search for some digestive help has led to the deaths of an unusually large number of birds along mountain highways this winter.
Entire flocks of finches and other small seed-eating birds pecking for grit have been turned to roadkill by snowplows and other vehicles.
Heather Murphy, a retired U.S. Forest Service wildlife biologist and consultant for the Wenatchee and Okanogan National Forest, said she noticed the problem while conducting bird studies for a Leavenworth volunteer birding group, the Upper Basin Birders.
Murphy said volunteers found three areas of roadkill finches Saturday on U.S. 2 between Mill Creek and Smithbrook Road a half-mile west of the Stevens Pass summit. She said they found small numbers of birds, fewer than a dozen at each site, although greater numbers were reported earlier in the winter.
Dan Stephens, a Wenatchee Valley College biology professor, said the problem is unusual and quite severe this year, especially along U.S. 2 near Stevens Pass and I-90 near Snoqualmie Pass.
“The finches are mainly attracted to the grit on and along the highway,” Stephens wrote in an e-mail. In the process of picking up the grit needed to aid their digestion of seeds, they ingest salt and other deicer chemicals used to keep the roads free of ice, he said. “The chemicals cause disorientation and sluggishness resulting in ‘grill birds.’ It’s a sad story.”
The state Department of Transportation uses a liquid magnesium salt deicer as well as calcium chloride salt on mountain highways to control buildup of ice and snow. “Grill birds” refers to birds that are hit by oncoming vehicles.
“I was stunned and horrified. It’s terrible,” said Derek Sheffield, a Wenatchee Valley College English professor and avid birdwatcher. Sheffield said he was cross-country skiing near Stevens Pass recently when he noticed that the snowbank along U.S. 2 was blackened by some sort of litter. On closer inspection, he found the litter to be dead birds. He said there were hundreds of pine siskins, a tiny brown bird that feeds on seeds and cones of alpine vegetation.
Sheffield, of Leavenworth, said he started talking to other birders in the area and found out there have been many reports of huge numbers of birds killed along U.S. 2 between Stevens Pass and Leavenworth.
The state Department of Transportation is aware of the problem, but isn’t sure what can be done, said Kelly McAllister, a Transportation Department biologist in Olympia.
McAllister said he’s been studying the situation to try to understand why large numbers of birds are on the highway. He believes an unusually large number of finches stayed in the area through the winter because of an abundant crop of pinecones this year.
The finches feed on the seeds from the cones, but they need to also ingest small pebbles and grit to help break down the seeds in their gizzards before the seeds pass to their stomachs. The sand on the road is a good source of grit, especially in this particularly snowy year when there are few patches of bare ground to be found at high elevations, he said.
McAllister said he’s not sure whether it’s the road grit found in the sand or the salt from the deicer that’s attracting the birds, nor does he know for sure why the birds aren’t flying off before a vehicle comes along and hits them.
“I’ve only been here a year, but people tell me they haven’t seen this problem before, at least not in the past several years,” he said. McAllister said the agency will study the problem but he doesn’t know what alternatives there are to the salt products that are as efficient at keeping the highways clear.
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