Pupillary Response of the Screech Owl, Otus asio.

The latent period of constriction in the owl is only half that in the human, and the latent period of dilatation is about equal to that in the human. Similarly, the rise time of constriction in the owl is much faster than that in the human. The owl system has the characteristics of a low-band-pass filter. The owl's frequency response is over an octave lower than that of the human, but its phase lags are shorter.