Asio otus
A medium sized, brown and long-winged owl, with long ear-tufts and deep orange eyes. Only half the size of Eagle Owl. Differs from the more similar Short-eared Owl by darker (orange) eyes, longer ear-tufts and heavily streaked lower belly. In flight, note paler wing-tips (only finely barred, not tipped black).
Song a series of very deep, monotonous "hooooo"s, quite widely spaced. Uttered about once every 2-3 seconds. Sometimes rises in pitch, but with each "hoo" being constant. Rich repertoire of calls. Other sounds include; a nasal "eeeeeaaa" reminiscent of Collared Dove, nasal mewing and bill clicking.
Wikipedia: map (se also Xeno-canto below)
Birdlife ecology