Great horned owls. Except for the only exception feasible- Which is of course the Great Grey Owl who has decided to move to southern NH from its previous home in frigid Canada– the GHO is the ultimate, TOTL, high-ender of the hunters in New England at the very least. There is a reason all the other members of the animal kingdom hate these “Bubo” eagle-owls as much as they do. GHO’s have every trick in the book, every bell, whistle, and gadget, making the whole evolution game seem wholly unfair to, say, an unassuming chipmunk. I wanted to give a quick rundown of the key toys and tools the GHO has at its immediate disposal, why I care, and why everyone else should care.
By shudrburg – http://www.flickr.com/photos/shudrbug/1502256414/in/set-72157594307880833/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=2882446
1. The “ears”
GHO’s ears are essentially their entire head. The poky things are literally there to throw folks off, though the idea was originally to emulate some bark or a pair of pine cones, some think… Though horns, ears, or party hats are probably ok too. As I say above, one could say with a fair amount of accuracy the entire head is a single, huge ear; Those pretty concentric eye rings? Chamfers and fillets on the face? these are funneling, extracting every scuffle and heartbeat falling in the laser-like path of the big, round, swivel-face. Remember: these owls are seeing with their ears. The GHO is always sleepy during the day, even while other owls might be a bit active- ruling out light as a reliable system for vision.
Below I snipped a good description of the GHO system. The asymmetrical face construction of a GHO also is used for “vertical” hearing- check this out:
“An Owl uses these unique, sensitive ears to locate prey by listening for prey movements through ground cover such as leaves, foliage, or even snow. When a noise is heard, the Owl is able to tell its direction because of the minute time difference in which the sound is perceived in the left and right ear – for example, if the sound was to the left of the Owl, the left ear would hear it before the right ear. The Owl then turns it’s head so the sound arrives at both ears simultaneously – then it knows the prey is right in front of it. Owls can detect a left/right time difference of about 0.00003 seconds (30 millionths of a second!)” (taken from: http://www.owlpages.com/owls/articles.php?a=6)
Obviously, anything can hear something more in the left ear and less in the right ear and know roughly where it is. However, “roughly” isn’t in the GHO vocabulary. Other studies have shown how owls crunch sounds at .00003 seconds; accuracy comes at the price of wildly complex brain structures that are solely used to draw auditory conclusions. Think; each ear has a set of pre-decision-making brain structures, analysing in parallel both the intensity of incoming sounds and the passage of time- synced perfectly to the other ear’s set and the brain as a whole. Look at it this way; the GHO sensing system, with its multiple super-computing cores is physically 3 times the size of the one found in our usual “smartest local birds”- the crows and ravens. No wonder the owls are always being bothered by crows- they must be so jealous! (and GHOs are a unrivaled predator to crows if the tides turn nasty)
2. The wings
Firstly, our local owls are dialing in around 10lbs of lift capacity. This makes even fat wild bunnies a piece of cake, no pun intended. Supposedly, these wings are rather disproportional to the usual bird weight/wing lift ratio, though I wouldn’t know. Just assume the owl can lift around 2.5 times its body weight, at least as far as a nearby pine tree to start snacking.
More importantly however, these evidently powerful wings are dead silent. The legend goes the mouse has no idea about its rapidly nearing demise until it feels the claws come in from above. I personally believe this to be 100% accurate- every possible flight detail has been subject to evolutionary innovation, from the crinkled, broken shape of the beefy coverts and wrist to the micro-turbulent primary and secondary feather structures, all the way to those huge, fuzz-covered legs and feet. These oversized fluffy feet, by the way, have a clamping force beginning to enter young snapping turtle territory… …You have been warned.
The micro-turbulences generated by the wings has sparked much intrigue over the years. Each feather exhibits a subtle, diffusive, “spiky” shape- the idea being the “ripping” and whooshing of air you hear from most birds when they take off can be removed by softening the hard edges of the feathers and wing such that the overall acceleration and lift isn’t hindered. This acoustic principle is really the opposite of how their faces work, diffusing sound instead of funneling it in. An intersting addendum in this GHO technology is how the coverts- the thick, leading edge of the wing- are formed. Many other predatory birds, like the local supercar of aviation, the peregrine falcon, bank on really sharp, hard curves and edges in the coverts to squeeze as much speed and maneuverability into these big important body parts. But not the GHO! Without sacrificing effective speed or agility, the coverts are sort of rounded and “broken up” into smaller edges and curves, directing the air and subsequently sound into a more diffuse pattern. Case to point: the mouse example. The general consensus on these coverts is these nubs are exactly the tool needed for the final swoop in to snatch the ground-dwelling prey. Even at a steep, speedy angle, the GHO can silently hurdle to the ground without spooking anyone. Amazing!
3. Other gizmos and gadgets:
The color and shape is its favorite spot to sleep. The local white pine trees, especially the trunk, are prime real estate for sleepy GHOs after a night munching- so, the owl naturally looks like a white pine tree trunk (complete with two pine cones on the top). Despite these owls being huge, they are rather common (in theory). The chances of finding one with human vision is essentially impossible, so we must rely on other clues on its whereabouts.
The digestion system is the best among owls. When the forest has been robbed of mice and chipmunks, GHOs can- and might even enjoy- eating frogs, big insects, reptiles, domestic pets… The trick is they simply eat the whole animal. There is no kerfuffling with fur here or teeth there; GHOs just go for it, 100% in. This may contribute to the widespread success in the north east, with our crazy weather and prohibitive geological extremes other species struggle with.
In conclusion:
I hope this has been both educational and convincing enough to be enthused about owling. Something this special and this relavent in the northeast is too important to ignore.
-Jess
