Tawny Owl


Tawny Owl
(Strix aluco)


Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Strix
Species: S. aluco


The Tawny Owl is one of the smallest Strix owls. It is a native of Europe. It has two to three distinct colour phases: red, grey, and an intermediate colour phase known as the brown phase. In this respect, it is much like the well known Eastern Screech Owl of North America.



Distinguishing characteristics:


The Tawny owl, or brown owl; is a typical Strix Owl. It measures about 37 to 46 cm (15 to 18 inches) in length. The wingspan is 81 to 105 cm (32 to 41 inches). The Tawny Owl's body weight varies from 385 to 800 grams (0.849 to 1.764 pounds). It's ear openings are asymmetrical in size, and idealy placed on the skull to improve its excellent directional hearing. It has the usual round, full facial disk, with none of the rings within it that is so typical of other members of this genus. There are no ear tufts. The loose looking fluffy plumage is characteristic of this genus. The eyes are brown. This Owl is very nocturnal and rarely seen during the day, even though it may be roosting well camouflaged nearby. The underparts are off white and streaked with a darker colour, depending upon the birds colour phase. The head, flight feathers, and wing coverts are a darker shade. They are cryptically mottled, and very closely resemble the pattern of rough tree bark.


Although sexually dimorphic in size, the largest males are actually larger then the smallest females, so this is in no way a reliable indicator of their gender. Small size and round appearance, with short tail and short, broad rounded wings distinguish it from all other owl species found within its range.



Habitat and natural range:


This species is found in mixed forest and deciduous forests, even in mature coniferous forests sporadically across temperate Eurasia. It can be found from Great Britain and the Iberian Peninsula, eastwards to India and western Siberia. It prefers to be close to water. It is strictly non-migratory. Semi natural areas near human habitation, such as parks, gardens, and even cemeteries; provide additional habitat for this species. Tawny owls are extremely territorial. Tawny Owls roost during the day on a horizontal branch pressed close to the tree trunk, preferably in dense cover. Their excellent camouflage protects them from being discovered most of the time, but they are still mobbed by diurnal birds, as are most owls.


Natural diet:


A wide range of small vertebrates are on the menu, with small rodents at the top of the list. Small birds caught roosting at night are also taken. Prey is hunted mostly by sound, and is caught completely by surprise due to this species well developed silent flight. The Tawny Owl has excellent directional hearing. It is so dependant upon hunting by sound, that it is known to starve to death after prolonged periods of continuous rainfall, which drowns out the noises it uses to recognize prey.



Reproduction:


The mated pair, which mate for life; maintain the same territory from year to year. Tawny owls are extremely territorial, and defense of the territory can be fatal. Nesting starts as early as February in the southern portion of it's range, but not until March in the northen limit of it's range.


Tawny Owls nest in the vertical natural hollows of old growth trees, and in the unused nesting cavities of large woodpeckers. They will also use man made nest boxes, squirrel dreys, and large cavities in unused buildings.


The glossy round white eggs measure 48 mm by 39 mm (1.9 inches by 1.5 inches) in size. The usual clutch is two to three eggs, with as many as 5 being laid in good years. The eggs are incubated only by the female. The incubation lasts for 30 days, and begins with the first egg laid. This means that the young vary in age and size within the nest. The owlets fledge at five to six weeks of age, but often leave the nest as much as ten days before fledging, clumsily perching on nearby branches.



Notes on Captive propagation (at the Centre):


We have found this species to breed exceptionally well at the Centre. However, we have one serious consideration: We have discovered that Tawny Owls will roost side by side like two peas in a pod, seemingly at peace with the world for months at a time. One can seem certain that they are a mated pair, and sure that they will raise a fine family. Then, much to our horror; with no prior indication or warning, one can turn upon the other and tear it into tiny pieces, which are draped all over the aviary. The reason for this is that even Tawny Owls themselves are not aware of what gender another Tawny Owl is until the start of the breeding season. If they are not a male and a female, or if they merely decide that they do not accept each other as mates, sooner or later this will be the certain and terrible result. Therefore, a great deal of careful consideration must be undertaken in order to avoid disaster. One must be certain of the genders of birds placed together to be paired up. Even then, careful planning must be done so that they are introduced in a way that their extremely territorial natures cannot get in the way of their efforts to mate. Once they are a confirmed pair then they will work together peacefully for life.


This species is fearless when defending it's nest and young, and attacks any intruder's head with its sharp talons. The fact that its flight is silent makes its attacks unlikely to be detected. Its very hard, if not impossible; to avoid the danger, which can be very serious. Proper precautions must be taken.


The first downy stage owlets are extremely active and bounce about inside the nest, much like fluffy animated popcorn. When they reach the second downy stage, they are incredibly cute balls of wooly fluff with a pair of warm brown eyes. This species quaint mannerisms and beautiful vocalizations make them a joy to captive breed. It is very well worth the extra effort to make sure that they are a compatible pair to begin with.



Circumstances affecting Conservation:


This species is vulnerable to avian malaria. The incidence of which has tripled in the last 70 years. Triggered by global warming, studies have shown that a temperature increase of as little as one degree Celsius produces a two to three fold rise in the fatality rate from malaria in Tawny Owls. In 1996 the fatality rate was only two to three percent. Whereas in 2010 it had risen to sixty percent in British populations of Tawny Owls.

Notice:

If you have found an injured bird of prey (hawk, falcon, owl, etc.), contact the Centre and our experienced staff can assist in determining what steps should be taken to ensure the bird receives the best possible care.

contact

Havelock, Ontario K0L 1Z0

Telephone : +1 705 778 5273

Email : staff