TAWNY OWL (Strix aluco)

Chouette hulotte

 

The Tawny Owl is found throughout the Western Palearctic region with a separate east Asia population. About a dozen sub-species have been described across this range with two colour morphs - a brown one (which is mostly in western Europe) and a grey one, the latter more common in colder areas and mountainous regions.

In Switzerland it is found in all forest/ woodland types up to about 1200m, but is more patchy in distribution as you get higher. This is the archetypical woodland owl, reasonably common throughout Europe. It is sedentary and pairs will occupy territories over a number of years.

In English the call is usually verbalised as "too-whit, too-whu" which most children know even if they have never heard one  - but this is wrong and mixes two kinds of call - and may have its origins in the song for winter which closes Shakepseare's play "Love's Labour's Lost":

When icicles hang by the wall

And Dick the shepherd blows his nail

And Tom bears logs into the hall

And milk comes frozen home in pail,

When blood is nipp'd and ways be foul,

Then nightly sings the staring owl, Tu-whit;

Tu-who, a merry note,

While greasy Joan doth keel the pot.

When all aloud the wind doth blow

And coughing drowns the parson's saw

And birds sit brooding in the snow

And Marian's nose looks red and raw,

When roasted crabs hiss in the bowl,

Then nightly sings the staring owl, Tu-whit;

Tu-who, a merry note,

While greasy Joan doth keel the pot.

 

 

The "tu-whu" part of Shakespeare's description is probably the common advertising call, which is a low-frequency series of notes best verbalised as "hooo-huhuhohoooo" with that final "hooo" prolonged and resonant and tremulous. It is a strong sound and in the quiet of the night can carry a long way, this bird was about 400m away when I recorded it with my parabola:

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The following is a recording made from about 50m, it is a long piece but gives a true reflection of the timing and the silence between calls.Closer up you can appreciate better the qualities of the sound, the first note rises and falls, this bird had a very brief second note leading to the third which is more prolonged and tremulous with almost a rasping quality to it:

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There are other noises in that last piece, rustling sounds are the feet of a small herd of Chamois in the dry leaves, they were slowly moving away from my approach, around 1.38 - 1.44, then again at 2.06 are some clear calls from overhead that sound rather like a Coot flying about.

The sonogram below gives two calls extracted from that last piece. I have focused just on the lower frequencies, the main energy is around 800 Hz but there are many harmonics above that, in the sonogram in addition to the base call you can also see the first harmonic at 1600Hz. Note how the first note rises from about 750 Hz to 850 Hz before falling back again, the third note is also not constant and the vibrato effect is clearly seen:

 

 

I have read that individual birds can be recognised by the pitch and degree of vibrato in their calls. Books often describe this as the male song, but in fact both sexes can make this call.

The "tu-whit" part of Shakespeare's description is probably a rendition of a more explosive call that sounds like "kewick". Birds use it to locate each other, and females will use it to respond to a male song, so it is often referred to as a female song,  but again both birds are capable of making this sound. Here is a recording from a noisy location which required heavy filtering:

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In addition to the above there are also a host of variations around these two most common calls. I cannot really comment and clearly need to find myself a breeding pair and spend a few nights in the forest !

 

 

 

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