January 22, 2016
Owls of Kane County
Thursday night I heard something I haven’t heard in several weeks: The who-huh-who-whoo-whoo of our nocturnal neighbor, the great horned owl.
Although they hooted and hollered their way through most of the late fall, their courtship period, lately I hadn’t heard much from the Bubos—my nickname for the great horned pair that dominates the avian territory around Davis School in St. Charles.
Bubo virginianus, you may recall, is the scientific name for great horned owls, or GHOs, a species that is common throughout our area.
Pairs mate for life and, even though bonded, will still go “courting” as they prepare for breeding. They select a nest that’s already made—a red-tailed hawk nest, squirrel nest, or even a large tree cavity—and get down to the business of raising a family just as winter hits its peak. While you’re warm and snug while outside temperatures are 0 or below, Mom GHO is incubating eggs. When you’re dry and safe in the midst of a blizzard, Dad GHO is bringing food to his growing family.
Then in spring, when you venture outside on those first warm days, the baby Bubos are fledging and preparing for life on their own. Timing, as they say, is everything, and in this case it couldn’t be more perfect–for the owls. Springtime is when most other birds and mammals are just starting to rear young so prey, in the form of immature animals, typically is abundant; and their inexperience is a boon for young owls, whose hunting skills often need lots of honing.
This approach to life works exceedingly well, not just for our local GHOs—which are present throughout Kane County—but for the species as a whole. Its range stretches from northern Canada throughout the United States and into Central and South America.
Back to the Davis School owls… Their courtship over, the pair has largely been silent these past few weeks. Thursday night though, something was up. I’m wondering if an owl with a neighboring territory encroached too far into the Bubos’ home range. Whatever the reason, the hooting was considerable.
Clearly the big birds were worked up about something, and I was glad that “something” wasn’t me. GHOs have long, sharp talons that make quick work of prey; powerful feet—purported to have a grasp stronger than that of a bald eagle; and a bill designed for ripping and shredding.
This legendary strength has enabled the GHO to extend its menu of possible prey to over 500 species, including such diverse animals as rabbits, mice, bats, skunks…and other owls.
Yep, the two other species we’ve profiled over the last couple of weeks, the barred owl and the screech owl, both are preyed upon by GHOs. In case of barred owls, the GHO is more likely to take eggs or nestlings; however, even adult screech owls—which top out around 10 in. in height and 6-8 oz. in weight—are easy prey for the 2-ft. tall, 3-lb. GHOs.
Which brings us to the results of our informal survey of barred and screech owl sightings within the Chronicle’s distribution area. As of yesterday we are at 12 people who have either seen or heard barred owls recently. The number of people seeing or hearing screech owls is at three, although I heard from another four people who, like myself, “used to” hear screech owls but have not for several years.
As we’ve said many times before in this space, populations of all species rise and fall as conditions change. Right now things seem to be favoring great horned owls and barred owls, while screech owl numbers seem to have dipped. Time—and any phone calls or emails to report a sighting—will tell how these owls sort things out amongst themselves in our suburban landscape.
Pam Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or potto@stcparks.org.
An eastern screech owl peers out from a nest box in Campton Hills. The box is outfitted with spikes to discourage squirrels from entering the prime winter shelter. Besides competition for cavity roosts, screech owls in our area also have to contend with predators including great horned owls and barred owls.
Photo courtesy of Bob Andrini.