Thursday, February 10, 2011
Experiencing the life of a Northern Hawk Owl
Over the past week, I've visited Sax-Zim Bog on two separate occasions. The first visit was with a friend from Hawk Ridge. We saw some wonderful birds, including a Northern Hawk Owl and a Great Gray Owl, all in the same day! The second visit to the bog was showing 5 friends around on a guided tour, and although we didn't see a Great Gray Owl, we saw nearly every other bird that can be seen in the bog! If that doesn't get the heart racing... I don't know what does!
Owls are unique and beautiful in their own way, but seeing them, in their preferred habitat is so cool! The Great Gray Owl and Northern Hawk Owl are both habitat specialists. A habitat specialist is a species that is found in a single/small variety of habit types. Northern Hawk Owls are typically a Canadian Boreal Forest species. Lucking for any nature-lover in northern Minnesota, there is a small stretch of Boreal Forest that stretches from Canada southward, along the North Shore of Lake Superior. Northeastern Minnesota is one of the few places in the entire lower 48 states to see Northern Hawk Owls!! Great Gray Owls love the Boreal Bogs, however they can also be found in mixed dense forests (thick deciduous over there.... coniferous over there... mixing in the middle) - yeah, that's what makes their home, their home. The most reliable spot to find these two owl species would be to visit a bog, and that's what Sax-Zim Bog consists of. A Beautiful Black Spruce Bog.
There is something about being there in the moment with these beautiful owls. To give you a feel of what it was like observing the Northern Hawk Owl, imagine looking at the owl shown in the adjacent photo. The falcon-shaped body and bull-headed owl turns to you... The beautiful yellow eyes produce a deep and almost trance-like gaze. The yellow bill is well insulated, tucked in the thin bristles around the bill (most birds have what are called rictal bristles, which are stiff "hairs" that line the outer edge of bill). The beautiful rusty-colored barring just glows against the contrasting head of the owl, which is covered by an elaborate helmet of black, white and subtle grays, and is even finer-detailed in white speckles. Now imagine this owl staring at you, then turning away in a quick and abrupt fashion. Movements with owls are quick and brief. Drawn-out movements can will only advertise the owls' presence. It doesn't take an owl to know that being mobbed by crows is unpleasant.
The owl stares at the snow in the other direction, away from you. It rocks back and forth, doing a little dance of shifting feet on the branch as the wind gusts test the owls' balance atop the branches. Northern Hawk Owls have well-insulated feet, to keep the feet warm during those harsh winter months which they experience every winter of their life. Quickly, the owl's attention is focused towards a slightly different spot in the snow... It triangulates (I will get back to the owl story in a moment)...
Triangulates? What the heck is that? The owl is actually hearing in 3-D! Here is how it works; Unlike humans, and most other living creatures that can hear, the owls have a unique ear setup (the ears are actually offset in non-symmetrical places on the sides of the head). It's a subtle difference, but by having one ear placed on the upper side of the head, and the other ear being lower on the opposing side, the ears will hear sounds at slightly different times. By having two ears independently located in different locations, the sounds that the bird hears will reach each ear at an ever-so-slightly moment. As a result of this, the owl not only hears how loud or soft something is, but also "hears" distance and depth. Here are two little tests that that you can do to see what I am talking about with the owls' unique senses.
Look at something complex in your house, maybe a cluttered desk, or a freshly-set dinner table, or maybe some birdfeeders out the back windows. Notice how you can see the far and close items, and get a sense of depth. Then, close one eye, keep looking at the same items, and notice how you cannot get that same depth perception. Your brain is only connecting a one-plane view to your eye, and that's what makes the view seem flat. Having two eyes open allow your brain to combine two angles into one "observed image," which produces the depth in what you see. The owl's ears work in a similar way with deciphering distance and depth. But, there's more that you have to do, in order to get a feel for what the owls hear!
Listen to some music, walk to the other side of the room that the music is playing in, and close your eyes. Relax. Cover one of your ears with your hand... wait a few moments, and try your best to point where the music is coming from. Tricky, huh? Your are hearing in a one-plane atmosphere. Now, take the one hand off your covered ear (eyes closed. no peeking)! Notice how right away, you get a sense of direction that the music is coming from? Now, even though this is beyond human, imagine combining the depth-deciphering abilities of two open eyes, with the direction-deciphering sound-listening abilities of two open ears, and make that an all-in-one sense of hearing. As humans, we don't hear in this complex manner, but this specialized sense allows owls to "see" under the snow, with their ears. :-) They can hear the little rodents running under the snow, and figure out exactly where the mouse is!
Triangulating is when the owls rocks the head back and forth, staring at once spot, to get a feel for "ok, with my head being here, the sound is that far. Now, with my head being a few inches over, the little critter is exactly there, under the snow." Now back to experiencing the Northern Hawk Owl...
So the owl triangulates, crouches, then freezes..... stands up again, crouches, and stares. The wind blows, but the owl is unaffected. Cars may drive by, and the owl is unaffected. Hyperfocusing has taken place, and the owl gets ready for an all-out hunt! It pounces off of its perch, wing are closed for a moment, momentarily looking like a feathered bulled. The wings flap once, twice, and the stealth-bomber wing formation takes place. The swift and near-silent owl hits the snow; then silence.
Immediately after piercing the layer of snow, the owl provides a complimentary talon-massage for the rodent. Birds of prey kill their prey using only their talons. A bill is never used to kill a live animal, as it is much safer to do damage at a distance (with long legs), than for the owl to risk potentially lose an eye, fracture a bill, etc. The owl flies up to the nearest snag, to enjoy a well-earned meal.