The Owl Diary: Week 2

I have lived in Colorado most of my life and camped in or hiked among the Rockies often. But this summer I am becoming acquainted with these mountains on a much deeper level. As part of a crew of college students studying Flammulated Owls, walking far off the beaten path is a given. Furthermore, we are out at night. Getting lost is not so easy though; the crew is almost always in radio contact and everyone is equipped with a GPS device. Most of the time, one feels safe knowing the lay of the land: “Ok, I came off that ridge to the North and am heading South down an aspen bottom, follow the drainage North to get back.”

This week proved slow for catching owls although we heard them on most nights. On several occasions a male would circle the lure net, giving territorial calls from nearby trees but refusing to fly near the net. Nonetheless, we concluded the week with 2 new nests found (a total of 16 for both weeks).

One of the study sites, located off the Manitou Experimental Forest, will be pivotal in examining the effects of human-caused fire on the survival of owls. The Hayman fire, the largest in Colorado history, burned over 137,000 acres, leaving patchy habitat for wildlife. In some locations, trees are charred only at their base. At others, nothing but skeletal snags remain. A study of Flammulated Owls surviving in this less than ideal habitat will give clues to their reproductive success and survival. Perhaps more important than whether or not a pair of owls successfully raises a nest this year is whether or not they return for the next. Return to a nesting site is an indication of suitable habitat and high survival.

Last Thursday I accompanied two other students hoping to capture a female in the Hayman study area. Having found the nest cavity earlier in the day, we set out at night with a capture net and radio telemetry equipment. Capture nets are pieces of old mist net tied around a hoop secured to an adjustable pole. We construct these nets on nights when severe weather prevents owling. Placing the net over the cavity at dusk, we know the female will soon exit her cavity to defecate and stretch. Soon we hear the male giving location calls (he wants to make a prey delivery to the female). In order to reduce stress on the female, we lower the pole and allow the male to make his delivery. Then, in an act of crafty deceit, we move the net over the male and catch him instead.

This male is particularly feisty. He claps his beak and kicks his legs, like a toddler throwing a temper tantrum. As I take wing measurements he sinks his talons into my fingers, ferociously nipping my fingers with his tiny beak. He doesn’t seem to know how ill equipped he is for battling humanoids.

This male will receive a radio backpack. These packs are secured to the back with a drop of Super Glue and two elastic strands that wrap under the wings and cross the chest like a backpack. The elastic must be tight enough to stay on the bird but loose enough to prevent abrasion. After release, the bird will pick at his backpack fitfully, so it must be secure. A thin antennae wire runs along the back, poking out over his tail. Using a special antenna, we can locate the owl based on the volume of the emitted beeps, which are heard through headphones. Still vigorously clawing his captor, we release the owl and watch it fly off shakily into the night.

Few people see these specters of the night, much less hold one or get to be part of a very specialized study of them. I know how lucky I am when I hold a tiny, big-headed owl in my hands. We say we know little about these mysterious Strigiformes now, but imagine how much less was known 30 years ago before the study began. Hopefully, these intense studies of Flammulated Owls and their habitat relationships will result in conservation of their habitat and a greater overall appreciation for them.

2009-06-07T17:22:31+00:00