Well, it’s that time of the year again. At least it is in the owl world. Otis, the education owl at Medicine River Wildlife Centre, seems to think its spring and is feeling amorous.
How do I put this politely? OK, great horned owl is a good name for him. He has been responding when he hears a female voice. He cocks his tail up behind his back and puffs out the white underneath his chin. Then he goes down to the bottom of his cage, and, well, you can imagine what he does down there.
I was curious, though, whether “normal” great horns act in this way. The only courtship behaviour I’ve ever seen has actually only been heard when the male and the female call back and forth to each other. So Otis, being human imprinted, made me wonder if he is acting in typical fashion. So I got out my resource books and sure enough, I found the following quotation in Wild Bird Guides Great Horned Owl by Dwight G. Smith: “When singing, the male Great Horned Owl bows forward while simultaneously drooping his wings downward and cocking the tail upward. At each song, he puffs out his chest, displaying his white bib, which may help signal his location to a potential mate.” That just proves that Otis’ behaviour is totally instinctive, even though he thinks he’s human. He’s an owl so far as his hormones are concerned.
Whenever I do research like this, I usually find out things, other than the information I’m looking for. I had been told many years ago that we can differentiate between a male and female great horned owl hoot. The female is higher pitched than the male. That seems to be a consensus. But I used to think that the female has a five note hoot while the male hoots only four times. I am, apparently, wrong about that. Roger Tory Peterson states in Peterson Field Guides Western Birds, “Male usually utter five or six resonant hoots . . . female’s hoots are said to be higher, in shorter sequence.” Dwight G. Smith goes even farther. He says: “To advertise territory and call for mates, Great Horned Owls use a three- to seven-note song consisting of a low, deep whoo-hoo, woo whoo-hoo, or whoo, hoo-hoo-hoo, whooo, whoo, with all of the syllables falling on the same note.” I guess I’ll just have to count Otis’ hoots before I can lay this debate to rest.
It has been a day where a few of my preconceived notions have been disputed. I used to think that the question of whether or not owls mate for life was cut and dried. I had read that in bird species where the males and females look alike, the species who mate for life the female is bigger than the male. That makes sense because if they are mated for life, the males don’t have to have the extra size for fighting off other males or even for impressing the females. The females can use the extra size to increase their egg laying abilities and to help with the defence of the nest.
I had read this a number of years ago and it was actually in an article about dinosaurs. Scientists were postulating that because dinosaurs were related to birds, and The Tyrannosaurus Rex female was bigger than the male, it would logically follow that T. Rex mated for life. But what I’ve been reading today seems to contradict that notion. I can’t find anywhere that states that any of the owls we have in Alberta mate for life. Wayne Lynch in Owls of the United States and Canada says that there is a difference between the owls who are year-round residents and those that migrate or are nomadic. The year-round resident mates (Great Horned Owls fall into this category) “share a common territory throughout the winter. The pair are together very little at this time, but occasionally will cross paths.” Migrant owls, on the other hand, typically set up new territories every spring through they may return to the same general area where they bred the previous season.
Their transiency is not conducive to protracted pair bonds.”
From all the reading I have been doing today, I have found out that great horned owls may keep the same mate for several years but do not necessarily mate for life. In the Sibley Guide to Bird Life and Behavior, David Allen Sibley says great horned owls “may retain their mate from year to year, and some pairs remain together until one bird dies.
So the question is, do they or don’t they? I saw a nesting pair in Brooks three years in a row and knew that the female at least was the same bird. She was missing an eye and so it was easy to recognize her. I had assumed that the male was also the same year after year. Now, I question that. It’s too bad Otis doesn’t have a mate or he could have answered this question as well.
Judy Boyd is a naturalist with the Red Deer River Naturalists.