A night with the Flammulated Owl
Words by John Gioia; photos by John Gioia and Saraiya Ruano, guest contributors
Most of our evenings begin in anticipation of the territorial male’s arrival and the female’s subsequent flight. Earlier today, we found this nest as we combed the Manitou Experimental Forest near Woodland Park. Now, the three of us are sitting at the trunk of a tree, waiting for this pair of Flammulated Owls to begin its busy evening antics. As sunset approaches, arrives, and passes (these owls almost religiously respond to the movement of the sun), we hold steady. I stand with a thirty-five-foot pole, net attached, raised to the tiny cavity in the trunk of the tree. Kirsten Becker and Saraiya Ruano, also CC students, stand close by with a good view. Silently, they send me hand signals about nest activity while I steady the pole, waiting for the male to coax the female out of the cavity and right into the net.
Now it’s 9:30 p.m., and we still haven’t detected any movement. We begin to worry. Usually, by this time, the male has already arrived and escorted the female on a brief flight, during which she can finally relieve herself of nearly sixteen hours of incubation. It’s a messy moment since the Flammulated Owl, though it is the second smallest owl in North America, can expel enough feces to cover your palm after sitting on her eggs all day.
After two hours, there’s still nothing moving. We raise a tiny video camera (the “peeper”) to the cavity and it transmits a picture down to a screen that shows an empty cavity. Normally, we would be here all night, observing the adults as they deliver insects to their young. If we’re lucky, we might see an owlet taking first flight from its nest, which usually ends in a crash landing, after which we band, bleed, measure it, and then send it on its way. But the images from the peeper are clear: these owls have fallen victim to a nest predator, most likely the vicious Pine Squirrel.
Disappointed but not defeated, we pack up our gear and head for the ridge where we staked out another nest earlier in the day. We aren’t giving up that easily.
We are waiting for these tiny owls as research field assistants to Dr. Brian Linkhart, professor of Biology and Ornithology at Colorado College. During every summer since 1981, Linkhart has been chasing these miniature nocturnal birds around the forest, hooting and swinging nets. One of the leading authorities on Flammulated Owls, he has nearly perfected techniques of locating territories and nests and capturing adults and nestlings, the skills and knowledge he now passes along to us. Our goal is to find as many nests and capture as many birds as possible to record the owls’ activity and band newly born chicks. This helps Linkhart determine patterns in owl productivity, territory fidelity, and loyalty to mates, from which he can gauge the quality of forest habitats. Studies with the longevity and scope of Dr. Linkhart’s may bear important management and conservation implications in the future, especially for species such as the Flammulated Owl, classified as “sensitive” by the US Forest Service.
Classifying the owl as “sensitive” has as many repercussions for forest management as for the bird itself. The Flammulated Owl received this classification because of a preference for breeding in old-growth, mature, open-stand pine forests, a trait Linkhart discovered. This type of forest was common 300 years ago when small-scale forest fires helped shape its understory, but now, fire suppression has altered the way pine forests grow. Some hypothesize that human activity threatens the available breeding habitat for the owls and other animals dependent on this type of forest. It is important to monitor the development of the owl’s activity in order to understand how to manage forests more cautiously and maintain biodiversity. According to Linkhart, “the length of this study is quite long compared to most other studies of avian ecology. The data provide unique insights into how factors such as forest quality and environmental changes may affect the owls.” It is research that has brought home to a local community the serious effects of deforestation, fire suppression, and forest thinning.
In a broader sense, studies done on migrating species demonstrate the effects of climate change based on differences in dates of the onset of breeding and incubation over long periods of time. Since the beginning of this research, the start of breeding has advanced several days in the year—perhaps because when owls arrive in their breeding grounds, insect populations are booming due to warmer springtime temperatures. As a result of this unique summer fieldwork, the owl project has produced several senior theses and compelled some students to pursue further work in field biology.
At 11:48 p.m., in position at the new nest, we set the lure-nets in place and turn up the iPod speakers, which hoot male territorial calls. If done right, the lure-nets bully territorial males into flying directly into the net out of anger toward another male (the iPod) in their stomping grounds. Soon, we capture our first Flammulated Owl of the evening, and as we untangle it from the net, we see he’s an unbanded male, most likely a new arrival to the area.
I band him and take a blood sample while Saraiya takes wing and weight measurements. Under the guidance of Dr. Linkhart, we have learned how to band and take blood samples from these owls to learn more about their year-to-year fidelity to territories, mates, and genetic characteristics. I slap on a Fish and Wildlife Service band and take a blood sample under his left wing, a vein equivalent to the large one right above the human elbow.
As Saraiya is finishing wing measurements, another male flies directly into the lure-net a few yards away. After untangling him, we see that he was banded nearly six years ago as a nestling and has returned to his breeding grounds—an unlikely feat for a bird that migrates thousands of miles to warmer climates every winter. Some ornithologists believe it is an evolutionary trait of birds to travel great distances from their original breeding grounds to limit inbreeding. In fact, this is only the sixth nestling banded on the study area by Dr. Linkhart and his crew ever to return to the area in twenty-nine years of ongoing research. We measure him and let him go, but not before snapping a couple of photos. The returning nestling was the 679th Flammulated Owl Linkhart and his crew have captured since the research began.
Now it’s past 12:30 a.m., and the night’s work is finally at a close. We head back toward our vehicle by the light of the full moon, pack up, and return to the lodge (a Forest Service cabin) for an evening wrap-up with the rest of the crew and some much-needed shuteye. It has been a long night, but capturing an owl banded six years ago makes it well worth the time. Tomorrow, we’ll do it all again. ∼