Tawny Owl (Strix aluco): Silent but deadly.
THE CRISP, FRIGID AIR OF A CLEAR WINTER'S NIGHT, shafts of moonlight beaming through the naked branches of woodland trees, your breath visible in front of you. The crunching underfoot of chill-stiffened leaves is the only sound to break the silence until a sharp, piercing 'kee-wick' echoes through the still air, assuredly followed by a wavering series of 'hoo-hoo-hoos', each inflected with a ghostly hollowness. This can mean only one thing, tawny owls are abroad, communicating in a style that has cemented their place in folklore for centuries. The common opinion amongst ornithologists and naturalists nowadays is that this is the male and female owl locating each other in their woody domain, with either call emanating from either bird in initiation or response, but never from the same individual in succession.
Wintertime is the noisiest time of year for the tawny owl (they become less vocally conspicuous once nesting is underway) and certainly a prime time to catch a rare glimpse of a roosting individual -- tucked up against the leeside trunk of a leafless tree -- who's aloofness is only occasionally betrayed by a baying mob of thrushes, chaffinches, tits and jays, indignant at the deadly menace in their sights: the owl, unflustered, won't even bat at eyelid in their direction. (If this is a favoured roost-tree of the owl, a pile of wretched-up, furry, bone crammed evidence will lie at the base; up to 4cm long and 2cm wide, these rounded pellets are the undigested remains of past meals that have been compacted in the bird's gizzard before being expelled.) Should you see the bird take to the air, the relatively short, rounded wings reveal its adaptations to a woodland lifestyle, aiding navigation through the tight spaces of the arboreal canopy where the infinitely variable control of wing geometry that feathers bestow allow it to move almost unnoticed by all but the keenest of senses.
The order of owls (know as the Strigiformes) step in where the daytime avian predators such as kestrels, sparrowhawks and buzzards (of the order Falconiformes) sign-off from their diurnal predations, making way for the owls to put their exceptional senses of sight and hearing to maximum advantage, and wreak havoc in the darkness of the woodland night. No mouse or vole is safe from the owl's stereophonic hearing -- asymmetrically placed ears sitting in cavities large enough to accommodate a human finger facilitate this -- whilst eyes containing retinas awash with cells, known as rods, provide superb black and white binocular vision, capable of piercing through the low light and pinpointing an unsuspecting victim with impeccable accuracy: targets are rarely missed and attain the size of small rabbits, dispatched swiftly with large, dagger-like talons. It isn't only ground-dwellers that are at risk, with small birds asleep in the treetops regularly featuring on the menu (finch and sparrow remains often show in pellets). As if the odds weren't loaded weightily enough in the owl's favour, soft, comb-like flight feathers assure near silent flight, providing the imminent quarry little chance of escape.
Owls have the remarkable perception of seeming to know, in advance, the numbers in which their preferred source of food (usually rodents and small mammals although tawny owls take fish, beetles and earth worms if necessary) will breed for the forthcoming season, and control their clutch size accordingly: in years of plenty, more eggs are laid; in years of poverty, the owls may not breed at all.
...eyes containing retinas awash with cells (known as rods) provide superb black and white binocular vision...
Swivelling its head round to watch me as I make pictures, the tawny owl's excellent vision is enhanced by its remarkably flexible neck. Contrary to popular belief, they cannot turn their heads through 360°. Photograph made at Wing and A Prayer Wild Bird and Owl Haven.
Stealth is the name of the game for the tawny owl, making diurnal sightings of the birds extremely rare. They are masters of disguise and only occasionally have their immediate location given away, usually by a flock of agitated passerines. Photograph made at Wing and A Prayer Wild Bird and Owl Haven.
Making a living during the hours of darkness, tawny owls seldom offer the naturalist any more than a cursory glimpse of their form. Be under no illusions though; they will almost certainly be watching your every move in their woodland home. Photograph made at Wing and A Prayer Wild Bird and Owl Haven.
The tawny owl's global range is quite vast, stretching from Western Europe and Northern Africa, across into Asia, Iran and into southern China, even touching the lower slopes of the Himalayan ranges. However, it isn't necessary to travel this far to get a rare sighting of one of these elusive birds, with Norfolk holding a healthy population wherever there are wooded areas containing a good selection of fine old trees: even our parks and sprawling urban gardens offer ideal conditions for the birds to live and breed. Late summer is the best time to study these creatures, when the young have fledged from their tree-hole cavity after over 2-months of incubation and constant attention from the parent birds (Only the female incubates the eggs, during which time the male supplies a regular source of food throughout the nesting period.) The juvenile owls, attired in a smokey grey plumage with hints of the flecked, coffee brown hues of adulthood poking through, will loiter around the tree tops at the emergence of dusk, waiting for an adult to deliver the first meal of the night. Be warned, however, should you be fortunate enough to encounter such a situation, as the adult tawny owls are known to be fiercely protective of their young, a fact that the famous pioneer of wild bird photography, Eric Hosking, will testify to: he lost an eye when approaching a nest site back in 1937 after being struck by a female fearing her young clutch was under threat.