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Ensuring songbirds keep singing

DWR program studies Utah’s songbird population

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EAST CANYON — The songs being carried outside bedroom windows each morning by those tiny, tiny songbirds come with a message: All's well.

It's when there are no songs that people should start to worry.

That, in simplified terms, is the purpose behind an ongoing study by the Utah Division of Wildlife Resources, a study believed to be the most extensive ever undertaken on songbirds on the North American continent.

The study is in its seventh years and is part of the Provo River Restoration program. There are 50 monitoring sites in Utah, but the two most closely monitored are in the riparian habitat above Little Dell Reservoir and along the middle Provo River between Jordanelle and Deer Creek reservoirs.

From May through August, wildlife crews will be netting, weighing, measuring, analyzing, banding and then releasing the small birds. Between 50 and 100 birds are being caught and released daily.

Protocol calls for nets to be set 12 times each summer at 10-day intervals.

This part of the study compares a disturbed site, which is the Provo River area where crews are in the midst of a restoration program, and an undisturbed site, in this case Little Dell.

"We take the data," explains Jimmie Parrish, project director and Utah Partners in Flight coordinator for the DWR, "to see if there are differences between the two sites . . . if the work along the Provo is disturbing the birds.

"Overall, we haven't seen a decline in these birds statewide. There are a few species we're concerned about, but overall the picture for birds in Utah shows no declining pattern."

By capturing rather than simply observing the birds, Parrish said, biologists learn more about the birds, such as breeding condition, sex (plumage in songbirds is not always different between male and female), a more accurate age, the amount of stored fat and if the females are past the first and onto the second or third clutch of eggs.

The importance of the study, continued Parrish, is not only in the pleasure the birds deliver in their songs, "but songbirds are a sensitive bird and indicate positive and negative things about the environment. We can use this as an indicator of how these disturbances affect all of us. If we see a major decline then it's a signal that something is wrong."

The birds also feed heavily on insects, like mosquitoes. The small birds are able to eat several times their own weight in a single day.

Thus far crews have captured 25 different species of songbirds above Little Dell. The most common is the yellow warbler, followed by the American robin. The rarest of catches is the least flycatcher.

One pleasant surprise, Parrish added, to come from the study so far is the discovery of the yellow-billed cuckoo.

"The first birds we saw were when the peregrine falcons were nesting on Hotel Utah and brought back two to the nest. We thought then that we had the cuckoos in northern Utah, but we didn't know where," he said.

"Since then we've found they've come back into the area along the Provo River."

Songbirds are all of one scientific family. They are a migratory bird that leaves Utah sometime in August and returns the following May to nest.

Parrish said the birds fly thousands of miles to wintering areas in Mexico and South America.

"Without any road maps to follow or pre-flight conditions, they will fly to a place they've never been to or seen and return to this same area," he said.

"Once they build up a fat supply, they go until they run out of gas, then stage until the build up more fat, and continue on."

They do all this traveling, explained Parrish, by sight. Songbirds have large optical lobes in their brains. The location of the sun and the length of the days trigger an urgency to gain weight and fly south. The same process, in reverse, sends them back to Utah.

"Some don't make it, but we do see a high rate of recapture," he added. "We average about a 16 percent return. Nationally that figure is around 10 percent. We see a strong site fidelity at all of our banding stations. Songbirds like Utah."

The study is expected to go on for two more years, at which time Utah will have one of the more extensive data banks anywhere on songbirds.


E-mail: grass@desnews.com