by Esther Lutz, East Central Illinois Master Naturalist for University of Illinois Extension in Coles County.
Crisp temperatures and early darkness signal the onset of October. As the leaves drift down and the day length shortens, we know that the autumn harvest season is underway. It seems like the only things passing me by as I walk on the roadway these days are pickup trucks and huge behemoths, otherwise known as combines, that span the entire width of the road as they creep slowly along.
This time of year, the short daylight and early dark remind us that there is an eerie holiday looming on the horizon. And in the natural world, creatures that work the night shift suddenly take on a new significance. Unassuming and forgotten at most times of the year, their elusive lives at night command a new fascination around Halloween, and their secretive nocturnal habits seem downright creepy. There is one species in particular that years ago was quite common around most farms and small towns of Illinois, but since the 1960's it has suffered a steady decline in our state.
Tyto alba -- Common barn owl. An owl with the word "barn" in its name would seem to imply that this bird would be a common inhabitant of the agricultural Midwest. But due to loss of foraging and nesting habitat and the widespread use of pesticides to kill their rodent prey (and indirectly, the birds themselves), these owls in recent years have become an endangered species in Illinois. The chemicals used in the pesticides also caused the shells of the eggs to crack before they hatched or prevented them from hatching at all. And years ago, humans shot the birds indiscriminately, believing they were a threat to small farm animals and poultry. They also unwittingly converted many of the owls' favorite hayfield feeding grounds to sterile corn and soybean fields, thus cutting back the wide open areas preferred by the birds for hunting.
Though Illinois is one of several states where barn owls are listed as endangered, this owl is likely more common than suspected in certain areas simply because it is very secretive and can remain undetected even when living in close proximity to humans. Unlike other owls, it calls infrequently except during breeding season (never hooting like some other owl species), and so we do not hear it announcing its presence as we often do with other owls in the night.
The barn owl is a cavity-nesting bird, and so relies on dead or hollow trees, old barns or other unoccupied buildings for roosting and nest sites, and requires grasslands and other open areas for hunting down prey. It is believed that the replacement of old wooden barns by metal ones, and the practice by modern farmers to eliminate hedgerows and wild areas on their farms are reasons for the decline in barn owl populations. Fortunately, these owls will readily use artificial nest boxes so that habitat restoration combined with nest box erection programs may help to reestablish their numbers in the coming years.
The barn owl has a unique shape and color and thus is easy to distinguish from other owls in Illinois.
It is primarily white with buff, yellow, or tawny shadings. The barn owl's face is its most arresting physical feature. It has no "ear" tufts at all, and the small dark eyes and pale beak are completely encircled by a heart-shaped facial disc that is white with a brownish edge. The dark eyes look forward in a fixed position and cannot move from side to side as our own eyes can. The owl must turn its whole head in order to see to the side or back (almost a full 180 degrees). It is able to see extremely well at night, and though it cannot see in total darkness, it is still able to fly quite well in light so dim that a human being could not navigate.
While the barn owl has excellent night vision, its ears may be even more important for locating and catching food. It has exceptional hearing and is able to hunt down prey in total darkness simply by honing in on the footsteps and nibbling sounds that rodents make. It specializes in hunting small ground mammals, and the vast majority of its prey includes small rodents such as voles (field mice), mice, and rats. Other prey include anything else it can find such as shrews, bats, baby rabbits, frogs, lizards, birds, or insects.
The breast and wings of barn owls are delicately flecked with dark specks, and the unique blending of light colors has led to many nicknames such as Ghost Owl, Monkey-faced Owl, White Owl, Silver Owl, Night Owl, Death Owl, and many others. Males and females are similar in size and color, and the bird stands just over a foot tall with a three-foot wingspan. It is medium-sized as owls go, and though of good size weighs only about a pound. Its low weight compared to its large wing size enables the bird to fly slowly and deliberately on silent wings over open spaces while it searches by sight and sound for its prey below. Its long, slender claws grasp the animal and scoop it up, after which it is torn apart and swallowed, fur, bones, skull, and all. The parts that are not digested are formed into pellets and eventually regurgitated at the roosting site or about the nest.
Perhaps the most eerie and unsettling feature of the Common barn owl is its voice. Some owls hoot, some hiss and others squeal, bark or coo, but the barn owl emits what can only be described as a blood-curdling scream! I can honestly say that I heard the barn owl's harsh, raspy screech very late at night a couple of years ago while lying half-asleep in my bedroom. It was a crisp, cool autumn evening and the windows were open. The scream was sudden and loud, and it sounded like an animal in great distress. At the time I had no idea what kind of night creature was making the sound, but it was unsettling, it was eerie, and it was utterly spooky! It's hard to imagine a more haunting call in all of nature. If I had had the courage to venture out into the night and shine a flashlight upward, I might have caught a glimpse of a shadowy, ghost-like creature with white undersides gliding silently over the landscape on its evening hunt. But at the time, I didn't know what was making the sound. Needless to say, I stayed put.
As it gets nearer to Halloween, it would seem somehow appropriate to catch a glimpse of a ghostly white owl silently winging over the field in its nightly search for prey. There aren't too many of them around anymore. We really have nothing to fear from them, and their heart-shaped faces actually give them a fairly non-menacing, sweet look. It's that eerie, distressing scream that is so hard to take. If I heard it again, however, I would consider it to be a good thing. Because that would mean that, once again, there's an elusive barn owl on the prowl.