Complementing the above said:
In Brazil we could also translate "Tawny awl" into "coruja comum ou coruja do mato" (Strix aluco
), with her color "castanho" interpersed with "castanho amarelado".https://pt.wikipedia.org/wiki/Aluco
It worth noticing that tawny has those meanings:
beige, bronze, browns, dusky, olive.
And that meaning of "redish-brown collor" (wich would lead us to the subject of wine - Tawny port wine...but then it´s just a side topic, to another opportunity.) http://www.thesaurus.com/browse/tawny