Owls are distinctive birds. Their forward facing, staring eyes; dished face: stealth and nocturnal life, which give them an aura of wisdom, power and mystery, are also attributes of an extremely sophisticated night hunter.
Owl eyes are adapted to night vision. Their eyes are large (up to 5% of body weight), and forward facing for binocular vision. Instead of eyeballs, their eyes are like tubes held in place by bony rings, the pupil of an owl can dilate to the very edge of the eye for maximum light exposure. Owls cannot move their eyes; they can only look straight ahead. To overcome this restriction, their neck is extremely flexible. Owls have fuzzy, low colour vision that is effective in low light and is highly sensitive to movement.
An owl's range of perception of auditory sounds is similar to that of humans, but its hearing is much more acute at certain frequencies, so that it can hear the slightest rustle in the undergrowth. Owl ears are vertical slits set on either side of their heads, in many species they are asymmetrical ie the slits are not level with . The facial disc of owls acts as a radar dish – the owl uses its facial muscles to alter the shape of the disc; this can amplify and funnel sounds to the ears. When a sound is heard, the owl is able to analyse the minute time difference between when the sound is perceived by the left ear, and when it is perceived by the right ear (owls can detect a left/right time difference of 0.00003 seconds ie 30 millionth of a second). They can also analyse the minute up/down difference in sound volume and pitch between the asymmetrical right and left ears. The owl raises a central ridge in its facial disc to prevent the sounds mixing. The minute left/right and up/down time differences fix the horizontal and vertical position of the sound; its intersection is the source of the sound and the location of the potential prey. The owl's brain has an instant mental image of the sound, space and direction and this is constantly corrected as the owl flies.
There are a number of owl species living on Tamborine Mountain, including the Powerful Owl, Sooty Owl and Barn Owl, the most common is the Southern Boobook whose distinctive call is often heard on the mountain.
Unfortunately owls face increasing threats such as clearing of vegetation which destroys their foraging, roosting and breeding habitat; loss of old dead trees with tree hollows; the proliferation of bright lights which disorient their night vision; barbed wire and netting which can entangle them; agricultural and household poisons and predation by domestic and feral animals. By preserving and replanting habitat, reducing light pollution, avoiding careless garden netting and keeping pets inside at night we can help our local owls survive.