During the breeding season, throughout the summer, a pair of owls may be heard calling to each other with a mewing sound. A hollow or crevice in an old tree is usually chosen as a nesting site, but walls of old buildings, rabbit holes and old nests of other hole-nesting birds may also be used. Once established, a nest site is often used year after year. No special nesting material is collected.
Three to five smooth white eggs are laid and the female usually begins incubating as soon as the first egg is laid, which means there is normally an age difference of a few days between each fledgling. Sometimes the female does not begin incubating until her clutch is complete. Hatching occurs after 24 to 25 days and the fledglings are covered with a creamy down which later changes to reddish-grey. The young owls are ready to leave the nest in three and a half weeks, but their parents continue to feed them for some time.Read More: Little Owls and Humans