I agree with Roopak that a photographic flash light causes momentary blindness. However continuous lights like the one used here helps the subject get accustomed as the pupils get adjusted to the light.

In the night normally the ambient noise levels are down. So it becomes easier to record the loud call of the owl. Sennheiser ME 66/K6 is a relatively cheaper shotgun microphone for recording distant sounds. Good to know that you record the sounds as well. That would help people identify subjects based on their vocalisations.