UCD Barn Owl Project

During our winter nest box checks we found over 50% of the boxes occupied and did not detect any signs of early breeding like last year. It is no surprise to us that Barn Owls at our study sites continually roost in nest boxes year round. In winter, nest boxes are important to provide safe roosting spots when crops and/or trees have no leaves for cover. Some owls have even held territory in the same boxes all year long!

We have seen owls come and go through the nest box networks we monitor, but this owl (-757) is our longest known resident. He has been holding territory at 2 nest boxes since 2018!

During the breeding season -757 uses one of those nest boxes for nesting and roosts alone or with his mate in the other box. He often double clutches (raises multiple nests in a single breeding season), and he has been documented breeding with at least 3 different mates over the years.

We are excited to still see him around on this round of regular fall nest checks!

Today we discovered a vineyard nest box full of nestlings that are 7-8 weeks old (nearly fledglings!) in mid-February... must be a sign of a good breeding season since the adult pair initiated nesting in *checks notes* November 2020 😳 🤯