VANISHING OWLS OF THE WASATCH—PART II

Here on the west slope of Utah's Wasatch Mountains, the burgeoning human population has affected wildlife in many ways. Some species have been losers, others have been winners. Part I of this post was devoted to a loser, the Long-eared Owl (Asio otus), a species that appears to be particularly vulnerable to the ravages of a big winner, the Raccoon (Procyon lotor).Since writing part i, I took a couple of moonlight cross-country ski trips through the habitat where these birds like to nest in clones of Gambel's Oak (Quercus gambelii). In this open country, it is easy to listen for Longears while keeping a good distance from potential nest sites. In the more rugged country where they nest in Bigtooth Maples (Acer dentifolium), it's harder to check on them this early without disturbing them. I watched a hunting Longear the other night, and heard a pair courting a couple of weeks ago. Sadly, I also saw two Raccoons in the vicinity that same night, so my hopes for their nesting success are modest.

Since taking a sabbatical from falconry in the early '90s, I haven't spent much time in the open marshy habitat favored by the Longear's cousin, the Short-eared Owl (A. flammeus), and can't speak to its current status in this area, nor can I say much about Pygmy Owls (Glaucidium gnoma), which have always appeared to be rather uncommon around here. Unlike the misanthropic Longears, the successful Great Horned Owls (Bubo virginianus), Screech Owls (Otus asio) and Barn Owls (Tyto alba) don't mind having humans around. All three species are doing well here, and nest commonly right in Salt Lake City. Burrowing Owls (Athene cunicularia) have suffered a population drop recently, but I think this can be attributed to a drying trend over the past two decades, causing a steep decline in vole (Microtus spp.) numbers. Unable to find sufficient voles to feed on, Badgers (Taxidea taxus) have widened their menu preference to include the owls. I've never found Saw-whet Owls (Aegolius acacicus) in the city, but these birds don't seem to be otherwise picky about their habitat, and appear to be doing well in many areas.

The last local owl species is in many ways my favorite. The gregarious little Flammulated Owl (Otus flammeolus) lives in old mixed forests at high elevation. When I found my first Flammulated colony at age 13, the literature described it as one of North America's rarest owls, and I thought I'd found my ticket to ornithological stardom. Actually, in the proper habitat, they can be exceedingly common, they are just very hard to observe, as they normally stay more than 20 feet from the forest floor, where their beautiful black, white, gray and cinnamon plumage is usually obscured by thick foliage. Summer is short at the altitude these birds prefer, and their appetite for insect prey can only be satisfied during four months. The youngsters develop very quickly, and leave the nest, an abandoned hole of a Hairy Woodpecker (Picoides villossus) or Williamson's Sapsucker (Sphyrapicus thyroideus), at about three weeks of age. Unlike our other local owls, the Flammulateds actually fly some distance south for the winter.

Dependent as these birds are on old, dead standing trees, they have come into direct conflict with the ghastly subdivisions that seem to proliferate like cheatgrass up every draw. Unfortunately, such subdivisions spread within a mile of both Wasatch Flammulated colonies I knew. In a preemptive effort to protect their ostentatious investments from fire, the human residents cleared all the dead wood from the area, and the Flammulated colonies were annihilated. So far, discreetly placed nest boxes have remained unused, but I continue to experiment with different locations and designs. Today I built four new boxes with a slightly smaller aperture that I'll install later this week. I only hope that a lack of nesting sites is the only thing keeping the owls away. I fear that the tidying of dead wood may have reduced insect numbers below a point critical for the Flammulateds.
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illustration: FLAMMULATED OWL (1990) acrylic 15" x 20"