By Ben Prego, GWCT Farmland Ecology Placement Student
The breeding season is moving along swiftly, and the pair of breeding barn owls within one of our Owl Box Initiative project nest boxes can frequently be seen continuing to cement their bond with one another. Courtship behaviour is an important part of bonding in breeding barn owl pairs and begins over winter and throughout the nesting season.
Owl Box LIVE Footage: Barn owl pair bonding
What happens inside the nest?
Barn owls do not build a nest, instead females lay eggs directly onto the previous years’ nest debris. This debris is made out of a compacted layer of regurgitated pellets, consisting of undigested animal material such as bones and fur. After each night’s hunting an owl regurgitates 1 or 2 pellets which takes about 6 hours or more to produce after feeding. Females may make scrapes in the debris to break up a few of the layers of pellets and this creates a softer layer to lay eggs on. First-year birds tend to breed a little later than the older, more experienced birds and these early laying females tend to have the best food supply and more successful breeding.
Courtship behaviour between paired owls
Once well-established in their nesting site, the barn owl pair continue to engage in mutual preening and cheek rubbing as a form of bonding. During this time, the female does progressively less and less hunting as the male brings food to her. Her weight increases from about 350g to 425g when she reaches what is known as “breeding condition”. Copulation occurs each time the male brings food to the nest. He stays present at the nest site for most of the time in the 2 weeks leading up to egg laying.
The male barn owl (right) has provisioned the female (left) with a rodent. He continues to provide food while she reaches a ‘breeding condition’ weight, and throughout egg laying and incubation.