Owls had been in & out of the Prey Box nabbing treats throughout the night.
Do owls see in color?
From The Barn Owl Trust:
The retina of an owl's eye has an abundance of light-sensitive "rod" cells which are very sensitive to light and movement, but they do not react well to colour. An Owl's eye possesses very few "cone" cells that do react to colour, so most Owls see in limited colour or in monochrome.
However, not much research has been done specifically on Barn Owls colour vision, so it's difficult to say whether they can see red or not.
You can read more about the Barn owls Adaptations by clicking the link