Western tanagers flock to valley
They’re everywhere this spring — small birds with a bright red-orange head and face, yellow body and black wings. The colorful birds seen perched in trees and on fences throughout Cache Valley are male western tanagers. Female western tanagers are abundant also, but their toned-down plumage makes them more difficult to spot. They have an olive green head and face, underparts that vary from bright yellow to grayish white, and a gray back and wings.
The notes in my old copy of Birds of North America say that I saw my first western tanager on May 31, 1993, on a hike to the Wind Caves. Sightings since then have been few and far between, mostly because I’m only a casual birder who doesn’t even own a bird feeder. But this spring the numbers of western tanagers has dazzled me. Why the sudden upswing in numbers here in Cache Valley?
Kim Sullivan, an ornithologist and associate professor in biology at Utah State University, offers an explanation: “Western tanagers breed in forests, but due to the late snowfall in the mountains and cold weather this spring, they’re staying low for food.” She goes on to explain that insect emergence is controlled by heat, and as the temperatures rise over the next week, the mountains should experience insect hatching, allowing the birds to make their way to their usual breeding habitat.
Val Grant, president of the Bridgerland Audubon Society, offers an additional reason for the increased western tanager presence.
“They may have simply experienced a population eruption,” he said. “Last year was a successful year, so this spring there are more birds to return.”
He then went on to tell of a friend who was visiting Rendezvous Park last week. (It’s located on the west side of Highway 89-91 just past the Logan River Golf Course.) A flock of some 250 western tanagers flushed from the nearby willows. It’s hard to say who was more startled, Grant’s friend or the tanagers.
I joined Birdtalk, an e-mail list through utahbirds.org, as a way to find out more about the increased tanager population this spring.
From the responses to my question about the numbers of western tanagers, it seems that the colorful little birds’ numbers are up all along the Wasatch Front. Tim Avery, who lives in the Salt Lake City area and maintains the website timaverybirding.com, writes, “I have been birding almost 18 years and have never seen more than 20 at one time. Right now you can travel pretty much anywhere in the state and see western tanagers.” He notes that on a recent trip from Northern to Southern Utah he saw numerous western tanagers in every type of habitat.
There is some speculation that the sudden increase in this year’s western tanager numbers might have something to do with climate change affecting migrating patterns. When I put that question to Sullivan, she was quick to point out that it’s impossible to make such a statement based on one year’s observation. It would take a number of years to determine whether climate change is affecting the tanager population. She did note, however, that the localized weather patterns we’ve been experiencing this spring will likely delay this year’s breeding season for western tanagers in our area.
“Their typical breeding season is now,” she noted. “They’re usually up in the mountains at this point with males establishing territory.”
Sullivan maintains that once there are insects to feed on up in the forests, the tanagers will migrate there to breed.
If you’ve been bemoaning this year’s cold and rainy spring, you’re not alone. The western tanagers have been waiting out the cold too. When it finally warms up and the tanagers leave the valley, look for them up in the mountains this summer.
1 comment:
We have them outside of my house too!!
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