The Great Horned Owl, bubo virginianus, is currently engaged in courtship and nest building. This largest of North American owls is the earliest nesting species in North America. While other birds are trying to survive the winter, Great Horned Owls are courting and getting ready to lay eggs.
The male and female both call in loud, booming, very owl-like voices, back and forth to one another, in a spectacular duet. They engage in this after dark and often in a longer duet before dawn. Reports of owls calling on calm nights have been increasing since Thanksgiving. They are widely distributed and fairly common all over Cape Cod, but rather thinly spread. A pair has a rather large home range.
Historically, Great Horned Owls had been absent from Martha’s Vineyard. There are none on Nantucket. These owls were a rare and local species on Martha’s Vineyard; a decade ago the first and only known breeding pair was discovered. They pretty much did whatever they wanted, free of interference from others of their kind.
Great Horned Owls are widespread and fairly evenly distributed over all of North America. Ranging from north to south, east to west, the desert to the tropics, these birds have adapted to all environments. They are the largest owl species in North America and are very powerful birds. They can take all manner of prey, generally eating whatever is most abundant. One of their favorite foods is skunk. They are oblivious to the smell and are quite happy dining on these “tear gas” laden beasts. This is a good thing, especially from a Vineyard point of view.
When these owls first arrived, a family in Edgartown had been hearing these birds giving their booming-HOO-HOOO-HOO during daylight hours. They live near the State Forest in Edgartown, and they become accustomed to hearing these big owls calling during the day.
Now, everyone knows that an owl, especially the big Bubo, the Great Horned Owl, does not call in the daytime. This commentator has yet to locate anyone who has ever heard this species calling in sunshine at 2 in the afternoon. They don’t do it - except on Martha’s Vineyard. When told of this almost a decade ago I asked them to call when they heard it again, being the skeptic that I have become from decades of chasing down bird reports. They graciously agreed and several times I went and was amazed and delighted by diurnal calling of Great Horned Owls. Unprecedented and remarkable are two good words to describe this unlikely event.
This pair of owls acted as if they didn’t have a care in the world. The nearby family often heard the two birds’ duetting back and forth. It is good to be a Great Horned Owl, at the top of the avian food chain and a supreme predator. They have almost no enemies at night, but a few that would harm them in daylight hours if they could find them, especially in the open.
That is why most owls, superbly adapted to hunting at night, are nocturnal. Owls are built for stealth, not speed. They depend on surprise, waiting quietly in trees, looking and listening for nocturnal prey. To be out in the daytime they give up many of their advantages and are at risk from daytime raptors like Red-tailed Hawks, Ospreys, Peregrine Falcons, and Bald Eagles, which do not hesitate to attack an owl, instinctively hating these powerful raptors, in the daylight. The tables are turned after dark.
The family watching these birds reported that skunks all but disappeared from the area, a most welcome development. Apparently the owls felt secure enough to advertise their presence in daylight and hunt in the thick woodland at what would be abnormal hours for this species anywhere else. It didn’t take the owls long to get on island-time. There are now several pairs and they have stopped calling during the day.
