Eastern Screech-Owl (Megascops asio)
Whinny: A sharply descending, quavering whinny.
Trill: A long, low, mellow whistled trill, usually all on one pitch, but may rise sligtly towards the end.
Eastern Screech-Owl whinny and trill, November 21, 2011. Milwaukee, Wisconsin. One owl in the foreground is alternating whinnies and trills. Another owl, somewhat more distant, occasionally renders a short trill at a lower pitch than the first owl.