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A Bird's-Eye View

The Boreal Owls of Western Colorado

by Scott Yanco
[Reprinted from A Bird's-Eye View, August 1999]

It was cold as we stepped out of the van at the Grand Mesa National Forest Visitor Center in western Colorado. It was a change that had occurred as we climbed up to our present elevation of about 9,000 feet from around half that. Along with the temperature, the habitat and bird life had changed. As we rose, the sparse desert scrub we had grown accustomed to slowly gave way to taller aspen groves, and those, in turn, had been replaced by the pine and fir trees of the boreal forest we now stood in. Scrambling to pull on fleece jackets and parkas, we could hear Pine Siskins and Cassin's Finches in nearby treetops.

As members of Colorado Bird Observatory's "Mountains to Mesas" camp, we were watching these species and trying to catch fleeting glimpses of Red Crossbills, when a green pickup truck rolled into the parking lot. Chris Schultz stepped out, dressed for the outdoors in jeans, long-sleeved shirt, and a black Forest Service vest. He wore a hat over a mat of uncontrollable red hair. And his large moustache did not at all hide his ear to ear grin. "I hope you have some bug dope," he said; "the mosquitoes are terrible. Come to the Grand Mesa, donate blood!" We gathered in a circle around him, and he began to talk - about Boreal Owls, red-backed voles, snow, forestry, banding, nesting, fungus - he was so animated that he never stood still. It was clear that he loved his work.

This work was studying nesting Boreal Owls in western Colorado. Since 1992 he and Tom Holland, the project director, have set up nest boxes for Boreals or other small owls, such as Flammulateds or Northern Saw-whets. They have set up 200 boxes on the Grand Mesa, 100 on the Uncompagre Plateau, and 100 near the town of Gunnison. Each year, around two and one-half percent of the boxes have been used. The project is using the Boreal Owls as an indicator species for boreal forests. An indicator species is an animal or plant used to determine the overall health of an entire ecosystem. It is known that the owl's main food source is the red-backed vole, and the voles are especially important during nesting season when one nestling owl can eat up to half a vole each night. A nest may contain up to seventeen baby owls, meaning a male owl may have to catch as many as nine voles every night!

But it is also important to know what affects the vole population. Snowfall can affect the voles in spring: if there is a high percentage of water in the snow, it can flood the voles' burrows during the spring thaw, delaying or eliminating vole breeding. The voles' diet consists mainly of fungi and lichens, especially a fungus known as Endogone, which grows in dark, moist forests. Through this chain of organisms, logging can affect Boreal Owls: more logging causes a less dense, drier forest, which means less fungi and lichen grows; voles have a smaller food source supply, so their populations drops; consequently, the owl population falls. But this knowledge lets the Forest Service monitor owl populations and is crucial in determining the amount of logging allowed within the forest.

When Chris finished, we all looked at each other smiling, uttering things like "That is so cool," or "Awesome." But one question still remained: how do you monitor Boreal Owl populations, especially in a place as large as the Grand Mesa, where before this project there were not even any records of nesting Boreal Owls? This question would be answered before our amazed eyes.

We clambered back into the van and followed Chris in his truck down a dirt road for a few minutes until we met up with Tom Holland. He looked like the typical outdoorsman: green flannel shirt, beat-up jeans, brown work boots, and a large moustache. Over his shoulder was slung a well-used camera. Chris told us that they knew this box was used and that we would find baby owls. How did they know? "Volunteers," Chris said. Every spring a massive volunteer day is organized wherein people from all over western Colorado break up into teams and systematically go to every box, scratch on the tree trunk, and see if an owl peeks out from the hole. Chris and Tom then go to the active boxes to band nestlings and, if they can catch her, the mother owl.

The banding itself is an elaborate process. First, Tom takes a large pole with a t-shirt tied to the end and creeps, as quietly as possible, to the box. He puts the shirt-end of the pole over the hole of the box to prevent the mother or any older nestlings from escaping. Then he and Chris carry the rest of the equipment to the box: ladder, climbing gear, a power drill, and banding tools. The ladder is leaned against the tree near the box, which is almost twenty-five feet high. Chris clips on his climbing gear and helmet and climbs up the ladder. The drill is passed up to him on a rope with a noose and used to unscrew the box's top. He carefully removes the baby owls and places them in small cloth bags, which are clipped to the rope and lowered to Tom. From the ground, this all seems to happen so fast that we barely get a glance at the owls before the bags containing them are passed our way. But we do not dare open them.

Two nestlings are lowered, and Chris climbs down. He and Tom pull the first one out of its bag, and cameras begin to click. It is a comically fierce little bird: black downy feathers, intense yellow eyes, and a bill that looks too big. It spends most of its time looking straight up into our faces, not so much appearing frightened as curious. It is weighed, and measurements are taken on the bill, legs, and wings. In addition, some blood is drawn for a study being conducted on the DNA of different Boreal Owl populations. The procedures are repeated on the second nestling, and the owls are returned to their nest.

We visited more nests that day; some were active, and some were not. But what an amazing experience to hold the nestling owl and have it stare directly up into your eyes. How incredible to think of the impact this study will have on thousands of acres of forest and countless organisms. It was a day that I, and the rest of our group, will remember forever.

About the author: Scott Yanco, lives in Medway, Massachusetts, and has been birding for over six years. This was his second camp with the Colorado Bird Observatory. Other than birding, Scott's hobbies include biking, camping, hiking, and soccer.