Great Horned Owl (Bubo virginianus)
A month after his vintage Peregrine Falcon sighting, birder Gary Reardon returns with another great sighting of a seldom seen bird, this Great Horned Owl. Owls are raptors just like hawks, but through natural selection evolved as a bird group fully equipped to occupy a nocturnal niche on our landscape. In fact “nightjars” (e.g. Whippoorwill), not hawks, are the closest relative of the owl. The Great Horned Owl is a “Typical Owl” from the family “Strigidae” which includes all of our owls except the Barn Owl.
The sensory capabilities of an owl include large fixed eyes with unique structures that allow vision in dim light and total darkness, and a head that can turn just shy of a full circle to capture it all. In addition, they have superb hearing which includes both closeable ear holes at different levels, and facial disks (for hearing, not eyesight) used to propel sound. The horns are called “Plumicorns” and are used for display with no hearing purpose. Thus owls can detect quiet movements such as rustling leaves from great distances. These features, along with light body structure attached to large, fibrously feathered wings, allow for efficient capture of large prey and near silent flight.
Owls are opportunistic carnivores and eat voraciously to maintain high metabolism during the cold winter conditions to which they are adapted. Having no crop, owls cough up pellets with undigested material including bones, feathers, and fur, and thus provide us with clues to their food sources. The Great Horned Owl, our largest and most wide ranging of our local owls, is a ruthless predator that can take prey as large as a skunk or Canada Goose! Unfortunately, prey items include other endangered birds such as plovers and terns. They are the earliest nesting owl which is known to incubate on nests filled with snow, and young are notorious for slow development. Owls don’t make nests but use cavities or nest boxes (smaller owls), or crevices of trees, or hawk or crow nests.
Occasionally heard at an owl prowl, the classic “hoo-h’HOO-hoo-hoo” call is heard from great distances. Optimal Great Horned habitat includes mixtures of forest and fields such as that found in our region and onto the Cape, where an increase in forest ages has resulted in increased owl abundance. Great Horned Owls call most frequently at dusk and dawn and often linger near field edges waiting for prey.