Gwendolyn
Gwendolyn, or Gwen, is a female Western Screech owl (Megascopa
kennicottii, formally Otus kennicottii). She came into the WSU
Veterinary Teaching Hospital in June 2004 with extensive injuries to her eyes.
She was most likely hit by a car. The damage to her eyes caused blindness in the
left one and severely limited vision in the right, making it impossible for her
to live on her own in the wild.
There are 3 types of screech owl in the United States. The Western
Screech, the Eastern Screech (Megascops asio) and the Whiskered Screech
(Megascops trichopsis). The Eastern screech owl is similar in color to
the Western Screech, but the Western has a much darker bill color. The Whiskered
screech is smaller than the other two and, has orange eye colored (as opposed to
yellow eyes that the two prior), and is more heavily barred. Geographically the
Western Screech owls are west of the Rocky Mountains, as opposed to the Eastern
Screech which are found east of the Rockies. The Whiskered Screech owls are
found in southern Arizona and into Mexico.
Western screech owls live in riparian (the green, vegetated areas on
each side of streams and rivers) or urban areas with mixed coniferous and
deciduous trees. They are among the smaller owl species (100g- 305g, the female
being an the larger end in all raptor species) and have small feather tuffs on
the sides of their head called "ears" or "horns" and are generally visible
when the owl is frightened or curious about something. They are cavity nesters,
nesting in tree hollows or nesting boxes. In contrary to their names Screech
owls don’t screech, instead they have a trilling "hoo-hoo-hoo" or a soft "cr-r-oo-oo-oo".
Screech owls are (primarily) nocturnal and hunt small rodents (preferably), but
since they are also opportunistic hunters (like most raptors) they will also
hunt; Amphibians, reptiles, small fish, insects, bats and small birds.
Screech owls, like all owls, have a facial disk, consisting a stiff
feathers around the beak and eyes, that direct sound back to their
asymmetrically place ears (The left is more up and forward and the right is down
and back). These adaptations allow owls to locate prey by triangulating sound,
without having to see it. Owls eyes make up about 50% of the skull,
however because their eyes are so big, they don’t have room for the extrinsic
eye muscles that allow other animals to move their eyes to look around. To
compensate for this owls have extremely flexible necks that allow them to turn
their head 270 degrees. They can do this because they have 14 vertebrae in their
necks (as opposed to mammals who only have 7) and the neck is "S" shaped. Owl
eyes are adapted for working in minimal light conditions (dawn, dusk, moonlight)
by having more light receptors, called rods. The size of their eyes and the
greater amount of rods allow owls to see much better in little light than other
bird.
One of the best known attributes to owls is silent flight. Their
feathers are soft and serrated at the edges of the flight feathers which reduce
air turbulence, muffling the sound. This both allows them to sneak up on their
prey unheard, but also without hearing themselves, giving them less distraction
to their hearing.
