Monday, October 13, 2008

Who Who Hoo's Out There?

Who, Who, Hooo’s Out There?
Dec 13, 2006

As humans, we usually consider January and February to be a rather quiet time of the year. The holiday season is over and the gardening can really wait for another month. However, with your window left open at night, just before you drift off to sleep, you can hear, not the prancing and pawing of 8 tiny reindeer, but the hooting and calling of some lust addled owls.
This is the time when their hormonal juices dictate that great horned owls reconnect with their lifelong mates, serenading each other with their particular love hoots (is this where hootenanny comes from?), bowing and touching bills in courtship.
The male, like most raptors, is smaller than the female but he has a deeper, more resonant voice, sometimes described as “hoo-hoo hoooooo hoo-hoo”. You’ll hear him first and then her higher-pitched, enticing replies.
Great horned owls are impressive birds. The largest of all our owls, they stand 18-25 in (46-63 cm.) tall with wingspans that measure almost 6 feet (145 cm.). They are easily recognizable by their cat-like face, with yellow eyes and two large “ear” tufts (not actually part of their ears). This feline resemblance has earned them the common names of cat-owl and winged tiger as well as hoot owl.
Great horned owls forgo the chore of nest building and will use large abandoned or commandeered nests, chiefly of red-tailed hawks, crows and magpies or snuggle into sizeable hollows or the broken tops of wildlife trees. Sometimes they will settle into the tangled mass of branches that we call witch’s broom (created by the parasitic but wildlife habitat enhancing mistletoe plants). Their most common nest tree in BC is an older Douglas-fir but they also routinely use western red-cedar, ponderosa pine and white spruce. There they raise an average of two young, with both parents sharing incubation and feeding duties. The young owls fly at about 9-10 weeks but remain with their extremely protective parents till the end of the summer, as they hone their hunting skills. Most great horned owls, after leaving their nest, rarely move more than 80 km from the area in which they were born.
Owl feathers have a soft texture and the front edge of the first wing feathers are toothed like a saw or comb, attributes which help the wind pass over the wings, enabling silent flight. Their facial disks are shaped like a bowl, which acts as a parabolic dish to help funnel sound into their ear openings, which are positioned unevenly on the skull, to assist them in gauging the location of their prey. Owls can detect a left/right time difference of about 30 millionths of a second! Most owls are active at night and to enhance their vision, have developed large, tubular-shaped eyes that are locked into their sockets. To make up for this lack of eye movement, they have double the number of neck vertebrae as us (14 to our 7), which enables them to move their heads up to 270 degrees and almost upside down. They are able to see 100 times more acutely than humans and if owl to human size were correlated, our eyes would be the size of oranges! Their sense of smell, however, is much less developed and explains why a meal of skunk is palatable!
All these adaptations have contributed to great horned owls being feared and successful avian predators who have very few natural enemies. Their hunting territories encompass about 100-300 ha. Generally edge habitats are favoured, that intersection between open space and forest which supplies significant diversity, allowing more hunting and nesting opportunities. Small to medium sized mammals (especially rabbits and rodents), and birds as large as ducks and geese form their diet.
Brave, foolhardy or driven by uncontrollable parental instincts, smaller birds, particularly crows, are often seen mobbing owls. Their loud, raucous cries and repeated dives are thought to be protective strategies to direct owls away from their young.
At the end of the rearing season, male and female great horned owls will go their separate ways, having a “holiday” from each other until the next breeding season, when they seek out their former mates. Listen for them.

Barred owls are the other large owl that can be found in Metchosin. Like many of us, they are new immigrants from the east coast, showing up in BC in 1943. The first barred owls I ever saw were a pair energetically mating at the Cook Rd entrance to 100 Acre Woods in April of 2000. I know you are not supposed to transfer human emotions and behaviours onto animal actions, but they sure seemed like they were having a good time! Their calls, screams and antics were something to be heard and seen, the kind of moment that confirms your commitment to nature. Their distinctive hooting has been described as the phrase "Who, cooks, for-you? Who, cooks for-you, all?".
Barred owls stand approximately 21 inches tall (46-58 cm.), have a round, puffy head without ear tufts, dark eyes and a vertically streaked lower front chest.
They are considered secondary cavity nesters, meaning they use cavities in trees but are incapable of creating the holes themselves. They must find either large nest holes that have been excavated and abandoned by woodpeckers or natural cavities that are the result of internal or external decay.
With the arrival of barred owls has been a drastic decrease in our smaller western screech owl, some people think as a prey item for larger owls. Barred owls are opportunistic feeders, consuming that which is easy to come by. They usually eat small to medium sized mammals and smaller birds, with the occasional lizard, amphibian or insect as an appetizer. Barred owls are notorious for attacking joggers along paths, perhaps mistaking bouncing ponytails for squirrels!
Mated for life, they start breeding around the end of March and raise their 1- 4 young for 4 months in their preferred nest trees of larger Douglas-fir (greater than 50 cm diameter) or black cottonwoods. The young leave the nest at 4 weeks and remain in the branches of trees until they are able to fly, at 35-40 days. Juveniles tend to disperse short distances, usually within 6 miles. Their only natural enemy is the great horned owl. Many of the larger owls have long life spans, 10-13 years in the wild and up to 29 years in captivity.
Whether enjoying a hike at dawn or dusk or resting at home with the windows open, Metchosin forests might provide you with the opportunity to see or hear these magnificently adapted birds of prey.

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