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Field & Street


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The Illinois Department of Conservation (DOC) is spending $180,000 to study the eating habits of owls. Last week both the Tribune and the Sun-Times ran versions of an AP story out of Springfield that told about the project.

I'm always suspicious of stories like this. They look like assembly-line productions: A reporter discovers a slightly offbeat item in the budget and then collects quotes from various legislators who know nothing about the project in question. The legislators can be relied on to declare themselves shocked, horrified, and disgusted at this flagrant waste of the taxpayers' money, and the headline writers can select something appropriate from their list of cliches for stories about birds. The Tribune headed its story "Feathers fly in debate on owl-diet study," while the Sun-Times told us "Legislators hoot, holler over state's owl study."

The $180,000 is spread over three years, and the project is being done by the Illinois State Museum on contract with the DOC. Russell Graham of the museum staff is in charge, and he has hired a field coordinator, Pam Gibson, to do or oversee most of the collections.

The study is possible because owls--like other raptors--swallow all parts of their prey, ingesting fur, feathers, bones, and shells along with the meat. The indigestible portions of the meal are then regurgitated in a pellet. Since owls typically return to the same roosting tree night after night, a researcher who can find the tree can collect all the pellets an individual owl casts. An expert--such as Dr. Graham--can then analyze the pellets and get a complete picture of the owl's diet.

Representative Ted Leverenz, a Maywood Democrat who is also chairman of the House Appropriations I Committee, declared, "Apparently the owl was wiser than we were"--a statement whose meaning I find rather obscure. His legislative aide said the chairman would like the money to be shifted into efforts to prevent poaching.

When I talked to Representa-tive Leverenz, he amplified his remarks, saying the study had already gone on for 18 months, 3,000 pellets had been collected, and it was time to call a halt to the proceedings. He suggested that Pam Gibson had been hired because she writes a newspaper column that is frequently critical of the department, and that since they hired her the criticism has stopped. He was also doubtful of the value of this kind of research and convinced that if it were to be done, it should be done with DOC staff rather than with free-lancers hired from outside.

I won't try to disguise my own bias in this case. I am strongly in favor of learning as much as we can about the natural world and how it works. In these times, such bits of nature as we have left exist only at our sufferance. Governments and private citizens routinely make decisions that affect the well-being of our natural areas, and we often don't know what the effects of our actions will be until we see the corpses piling up or realize that we don't hear as many different kinds of bird songs anymore.

However, while $60,000 a year for three years is not big money in the context of the state budget, it is the taxpayers' money and ought to be spent with care. Russell Graham made the same point when I talked to him. "I pay taxes too," he said, "so I have no problem with people asking me how I justify my research."

His justification began with the economic importance of these animals. They are a free pest-control device, and now that chemical pesticides are revealing themselves as a scourge, it is reasonable to look at alternatives, to find out just how much good owls can do us.

We should also study owls because they are of great importance in natural systems. Owls are top predators, the creatures at the apex of the food chain--a position that makes them very vulnerable. Poisons introduced into the lower links of the food chain ultimately find their way into the bodies of top predators. Since any perturbation anywhere in the system will ultimately show up in their lives, we can learn about the state of the whole system by studying them.

Predators serve a vital function as preservers of biological diversity. This has become a major concern of ecologists and conservationists, because diversity keeps the systems going--and diversity is what is most threatened by our destruction of nature. If you count the numbers of birds on a typical city block in Chicago, there will probably be more individuals than there would be in a piece of forest of the same size. But the city population will number far fewer species; the diversity is gone.

Predators preserve diversity by preventing any single species of prey animal from becoming too abundant. Owls go after the things that are easiest to catch. If deer mice enjoy a population boom, the owls will concentrate on deer mice until the population falls to a level that makes them hard to catch. Then they will switch to meadow voles or cottontails.

We also are very concerned with protecting endangered species, and several owls, unfortunately, are very much in danger. The barn owl has become extinct in Illinois. The DOC is attempting to reintroduce it, but so far its efforts have not been successful. The short-eared and long-eared owls are on the endangered list in Illinois. Making management decisions that protect these rarities requires good information.

Pam Gibson told me that her work so far has raised some serious questions about the status of the barred owl. This was once the most common owl in Illinois, but it seems to be disappearing from habitat where it once was found in abundance. The barred owl is a bird of river-bottom forests. In the Chicago area it is very scarce. We have a few birds along the Des Plaines River in Lake County, but none in Cook County. Gibson's research in the Illinois River Valley--which should be prime barred-owl habitat--finds the species missing from many areas where it ought to be abundant.

The study also provides baseline data that can be referred to in the future if we begin to suspect that harmful changes are occurring. I have written before about the problems we have in being certain that our perception of the decline of certain songbird species is real. Solid data from 1990 will be helpful in 2010.

Graham also notes that the study is following these birds through all four seasons. Much of our previous information was from fall, winter, and early spring. Collecting summer pellets is difficult. It is harder to locate the birds, and the pellets fall apart quickly in the warm weather. Pellets collected in summer on this project have already told us there is a major seasonal shift in diet. In winter owls concentrate on birds and small mammals, since that is what is around. But in summer they add reptiles, amphibians, crayfish, and surprising numbers of insects to their diet.

Gibson has found barred owls feeding for days exclusively on cut worms, loopers, and other insect larvae that are very destructive to foliage. This information was not known before the study began.

Graham also hopes that his analysis, when complete, will show how owls partition the environment between species. This is a major conservation question. If we find barred owls, great horned owls, and screech owls living in the same woodland, we suspect--based on previous studies of other species --that they are dividing the resources of the environment in ways that will minimize competition between species. They may hunt at different times of day, or in different microhabitats, or they may concentrate on different prey species. If we hope to maintain all the species in a woodland preserve, we need to know what they require and how they get along.

The question of partitioning is also vital to the efforts to reintroduce the barn owl into Illinois. Thus far, the pellets collected suggest that barn owls are competing with great horned owls for the same prey. It may be that they cannot establish themselves because they are being outcompeted. Perhaps some habitat manipulation may be needed to keep the species separated.

So the study seems amply justified to me. The first 18 months of collecting have been concentrated mainly in northern and central Illinois. The last 18 months will shift the emphasis to the southern third of the state.

There is that final charge that Pam Gibson got the contract to shut her up. This did seem unlikely to me. Pam Gibson is well-known in conservation circles in Illinois. She is invariably outspoken and completely indifferent to whose toes she steps on. Mention her name in a group of environmentalists, and you'll notice smoke coming out of the ears of some. But I don't think even her worst enemies would believe she could be bought off with a DOC contract.

I called her and asked about the charge. She said she didn't think I could print the reply she wanted to make. I assured her that we're pretty loose at the Reader. But she contented herself with blasting legislators from northeastern Illinois for "holding the DOC budget hostage until their own district is amply served." She then blasted the legislators and the DOC for funding a $1 million study of deer overpopulation in this part of the state that she said taught us nothing we didn't know already.

She then attacked the department for wasting over a million dollars on a downstate prairie-chicken sanctuary she characterized as a "declining zoo" that didn't contain near enough habitat to preserve the species. And she cited a recent newspaper column she wrote that blasted the DOC for inadequately protecting endangered birds in the Illinois River Valley from an Air Force proposal to use the area for low-level training missions.

Finally she pointed out that the owl survey is delivering a whole lot of research for the buck. She has a network of 100 volunteers around the state who are collecting pellets for free, and when she travels, she camps out rather than bill the state for a motel. "We even reuse our Ziploc bags for collecting," she said. She has also taken school ecology classes on educational pellet-collecting outings.

To me this project is the very best sort of thing to spend our tax money on. It is providing us with vital information at a very low cost. It is not wasteful. It is not a boondoggle.

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