Curious Nature: ‘Toot toot toot’ goes the northern saw-whet owl
Autumn’s north winds, cold temperatures, and long dark nights are what northern saw-whet owl banders dream about. Like many other bird species, northern saw-whet owls begin their southern migration to warmer winter ranges when autumn comes. As a former bird banding research assistant, the end of September meant preparing our banding site, near Upstate New York, for the arrival of migrating owls from more northern latitudes such as Canada or more northern states.
In the early 1800s, John James Audubon tied threads to birds’ legs to identify individuals that visited his farm. By 1902, the benefits of identifying wild birds were recognized with the first scientific study that incorporated bird banding with scientists of the Smithsonian National Zoo of Washington, D.C.
Currently, bird banding plays a crucial role in understanding the population dynamics of wild birds, juvenile dispersal, migration patterns, behaviors, and human management and conservation efforts. Today, bird banding is regulated by the federal government. Research scientists must apply to the USGS Bird Banding Laboratory for a special license to band birds.
Our focus, the northern saw-whet owl, is North America’s smallest owl. Weighing in between 75-105 grams, these owls have a white facial disk, black beak, brown head with white spots, vibrant yellow eyes, mottled brown body, and a white breast with downward reddish streaks. These owls migrate through Colorado every autumn, but some individuals reside here year-long because their prey of deer mice, voles, and chipmunks, seem abundant.
As a bird bander, we’d start before sunset. Each evening a long row of tall, finely-threaded mist nets were set up in dense forests of spruces and firs. And a recording of a northern saw-whet owl call was broadcasted to coax owls towards the nets. The calls sound like a series of whistled “toot-toot-toot” notes, similar to the safety alarm sound you hear when maintenance trucks are backing up.
Once caught, banders carefully and quickly untangled the owl and placed it in a carrying device that consisted of several 6-ounce tomato paste cans. The owls may look large when fluffed up, but are actually quite small and easily fit into the can.
A series of measurements were taken of each owl: age, sex, weight, wing length, wing arc length, and tail length. A uniquely numbered aluminum leg band was fitted onto the leg and released back into the night to continue their migration journey. The information gathered is submitted online to BBL for research use for publication in scientific journals and public education.
It is rare for an individual to encounter a banded bird. However, if you do see a bird that has been previously banded, it is essential to the success of the bird banding program that you report the bird to BBL. It can be interesting to learn where the bird was originally banded and when/how long it took for it to travel to where you found the bird.
According to BBL, from 2011-2021, 376 northern saw-whet owls were banded in Colorado (10 in 2021), seven of which were encountered a year or two later, including one that was banded in 2012 and encountered four years later all the way in Pennsylvania! Toot toot toot!
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