Most owls are nocturnal, actively hunting for prey only under the cover of darkness. Several types of owl, however, are active during the twilight hours of dawn and dusk; one example is the pygmy owl (Glaucidium). A few owls are also active during the day; examples are the Burrowing Owl (Speotyto cunicularia) and the Short-eared Owl (Asio flammeus). The time at which an owl hunts is correlated with the color of its eyes: dark brown or black eyes indicate nocturnal activity, orange indicates dawn or dusk, and owls with yellow eyes hunt during the day. There are exceptions, so the color of an owl’s eyes is not always a reliable indicator of its active hours.
Finding an owl during the day can be difficult but my friend the ornithologist (a scientist who studies birds). recommends the following tips.
Look for roosting owls in evergreen trees or dense vines. In trees, they will stay close to the trunk and choose a spot that are obscured by other limbs, which makes it difficult to pick out their distinctive shape.
Examine the ground at the base of likely trees for owl pellets—small sausage shaped bundles of fur, feathers, bones, beaks etc. Owls regurgitate at least one pellet a day: if a bird returns to the same roost frequently, there will be a number of pellets on the ground. A fresh pellet means you’re probably close to a roosting owl.
Check the ground and lower branches of trees for whitewash, the telltale droppings of a roosting bird.
Pay attention to other birds, particularly crows, blackbirds, magpies, even chickadees. If these birds discover an owl, they harass and mob it noisily. Roosting owls don’t move on easily, giving the birder time to discover what the crows are excited about.
Check evergreens lower down as well as tall trees: smaller owls will often roost at eye level.
Cemeteries, gardens and parks are good places to look if you live where there are no evergreen trees.
Some smaller species of owls will nest in buildings that have close access to water.