In the movie, on a few occasions, we see characters who have a strange gold like glow in their eyes. This is meant to suggest to us, the audience, that they are replicants (or animoids, in the owl’s case).
Note: The glowing eye effect was achieved by bouncing light off a half-mirrored glass mounted at a forty-five degree angle on the camera. An effect that is quite difficult to create (and even harder to accomplish by mistake…)
But note also that the owl was originally intended to be real – Rachael’s line was overdubbed to indicate the owl is artificial.
Posted in: 4.2. Glowing Eyes