Owls
By Rene Wendell
December 2009
Santa Claus is not the only occupier of the night sky this season. Along with ho, ho, hos there can be heard hoo, hoo, hoos from some of the Berkshires most extraordinary year long residents, our owls. Just like Santa these owls aren’t afraid of a little cold and are commonly heard this time of year now that the fall dearth of katydid song has passed and the leaves have all fallen from the trees. These calls can be carried afar on the cool and silent night air. It is always thrilling when I hear one in the tree line across the fields from my apartment. Sometimes they are so loud I am woken from a sound sleep.
Owls are some of my favorite birds. They have some fantastic physical adaptations to help them reap a living in the wild. In fact, the great horned owl is so successful that he has one of the largest home ranges of any birds found in North America, living from the boreal forests of the arctic to the far reaches of South America and inhabiting everything from sub-tropical to desert ecosystems. Great horned owls will sometimes prey upon animals 3 to 4 times heavier than themselves and will eat everything from other owl species, to frogs and fish, raccoons, porcupines, 
ducks, and great blue heron and red-tailed hawk nestlings. They are also one of the major predators of skunks even though they have a very poor sense of smell!
Occasionally, this time of year we may get a visit from a more northerly species like the great grey owl or snowy owl. These guys only come down when food is scarce in their home ranges up in Canada. And it is a real treat when they do! Our other year-rounders are the screech owl and the barred owl. The latter giving the famous who-cooks-for-you, who-cooks-for-you-all nighttime cry.
All this calling is in part to establish or reaffirm a territory. Our year-rounders have set ones and if you hear one by your home it is probably the same bird or pair of birds. The barred owl and screech owl mate for life while the great horned owl is solitary and only gets together for the nesting season. That is the other part of all those hoots...love. Courtship for some of these owls involves chasing each other around, calling from different braches, bobbing and swiveling their heads, and the male screech owl even winks with one eye at his girl!
Owls don’t make nests. The bigger owls will re-use old squirrel, hawk, heron or crows nests or will use ledges or tree cavities. The screech owl being very small (about as big as a Coke bottle) almost always uses tree cavities – either natural, made by a woodpecker, and I even know of a pair nesting in a man-made wood duck nest box.
Owls have always seemed to be revered by people. Although some Native American cultures viewed the owl as an omen of death, the Greek goddess Athena had an owl as a pet, and the owl today is synonymous with wisdom. Think Winnie the Pooh or Tootsie Pop. Maybe it is because of the those large forward facing eyes that are situated in the front of the birds face, just like ours. In fact, an owls vision is similar to that of people, being binocular and having great depth perception. Perfect for catching its prey.
Owl’s eyes are set within a sclerotic ring, a bony structure that prevents the eye balls from moving. Since they can’t move their eyes, owls swivel their necks to see around. Their heads can’t turn completely around but can go an amazing 270 degrees! They can do this by having 14 vertebrae in their neck – we only have 7 vertebrae in ours.
My favorite adaptation in some owls is their hearing. We have ear openings at the same point on each side of our head. Some owls have asymmetrical ear openings, one a bit higher up than the other. This allows the owl to hear a critter in one ear a slight moment before he hears that sound in the other ear. The owl can then instantly tell the direction of the sound and can then triangulate in on its prey.
Santa will soon be making his way across the night sky yelling Merry Christmas with all his jingle bells clanging loudly. Our owls are a little less flamboyant than that! When they fly it is silent and they do this by having fringes on the leading edges of their wing feathers. These fringes break up the loud turbulence that gushes over wings in flight. (The stealth bomber utilizes technology borrowed from owls. ) This not only makes for a silent approach on an unsuspecting mouse, but more importantly, there is no noise to interfere with the birds own hearing and ability to target in the dark.
About Rene Wendell - Introduced to nature by his father, Pittsfield, MA native Rene Wendell knew the names of wild creatures as a toddler. After living in Florida and Arizona Wendell returned to the Berkshires to obtain degrees from Berkshire Community College and the Massachusetts College of Liberal Arts and now works a conservation ranger for the Trustees of Reservations. As such, Wendell spends his days knocking back invasive plants, tracking rattle snakes, and teaching others about the great outdoors. He likes to hike, hunt, fish, bird watch, collect antiques, and go metal detecting with his 91-year-old father.