North Cornwall Barn Owl Report 2024

As we enter the winter season for 2024, it's time for us to start cleaning out our barn owl nest boxes, so we thought this would be a great time to reflect on what a brilliant barn owl year we have had. Here is our summary of our 2024 barn owl season!

30 sites visited and 33 chicks ringed!

During late spring and early summer, we conducted visits to 30 nest box locations across North Cornwall. Out of these, twelve boxes were occupied by barn owls. Among them, one box housed a healthy adult owl that had been previously ringed, while the remaining eleven were home to successful breeding pairs—meaning healthy chicks! In total, we ringed an impressive 33 barn owlets.

The season's highlights included two particularly productive boxes, each containing six eggs or chicks. Additionally, three other boxes held five eggs or chicks. As a whole this year has shown the largest clutch size in Cornwall since 2015! Head over to our colleagues at West Cornwall Bird Ringing Group for a countywide update!

Fun Fact: Staggered Egg-Laying in Barn Owls

Did you know that barn owls don’t lay all their eggs at once? Instead, there’s often a delay between each egg being laid, resulting in chicks of different ages within the same brood. This staggered approach is a survival tactic. In years when resources are particularly scarce, the younger, smaller chicks may unfortunately become food for their older, stronger siblings. While the thought of sibling cannibalism might seem grim, it’s a clever strategy that helps ensure the survival of the fittest individuals in challenging conditions. Nature always finds a way!

How Do We Ring Barn Owl Chicks?

Ringing barn owls can be quite a tricky task. These elusive birds are most active at dusk and feed through the night until dawn, making them difficult to catch. However, the most common and practical way to ring barn owls is when they're chicks, before they leave the nest. This timing not only simplifies the process but also helps determine the bird's age and location which is vital for studying their longevity and tracking their dispersal.

1. Visiting Nest Boxes

Between April and July, our licensed and experienced group members visit nest boxes, which are typically placed by landowners in barns or on tall poles in suitable habitat. To minimise disturbance, we carefully position a ladder close to the box. Using a phone or an endoscope, we check inside the box to see if owlets are present and assess if they are old enough to be ringed. Once the chicks reach an appropriate size, the adults usually vacate the nest temporarily—sharing a small space with five chicks can be a tight squeeze!

2. Safely Removing the Chicks

When we confirm the presence and age of the owlets, the next step is carefully removing them from the box. Fortunately, young barn owls are relatively docile during the day, making this task manageable. We gently place them in individual bags for safe handling.

3. The Ringing Process

After climbing back down the ladder, we begin the process of ringing and collecting biometric data. Barn owls require a G-sized ring, which can be challenging to fit properly. The ring must form a D-shape, and some may need a slight overlap. To ensure accuracy, all rings are thoroughly checked to confirm a perfect fit for each bird.

4. Returning the Owls to Their Nest

Once the ringing is complete, we return the owls to their nest box. To make sure they settle back in without escaping during the process, we temporarily block the entrance hole with a cotton bag attached to a long string, which we remove once the ladder is back in place. After a few minutes of observation to confirm the owls are calm, we leave the area.

Working with Cornwall Mammal Group to monitor our small mammal populations using Barn Owl Pellets

Small mammal skull photos by Louise Jarrett on her research project using owl pellets to monitor small mammals on arable land vs marshy grassland.

This year, we partnered with Cornwall Mammal Group to monitor small mammals in Cornwall using barn owl pellets—a fascinating tool for ecological research. Since barn owls can't digest bones and fur, they regurgitate pellets, providing a unique snapshot of their diet. While this might sound a bit unpleasant, it’s an invaluable method for identifying the small mammals that dominate our countryside.

This collaboration was especially important following a concerning record of the invasive Greater White-Toothed Shrew in North Cornwall. To investigate further, Dave Groves from Cornwall Mammal Group meticulously examined 557 prey items from the pellets we collected. Thankfully, no evidence of the invasive shrew was found.

However, Dave’s analysis yielded some incredible insights, including 145 shrew records, his second-ever bat record (from around 5,000 prey items), and his first mole! He also identified a couple of harvest mice, adding valuable data to help us better understand and protect local wildlife. This initiative highlights how barn owl pellets serve as a window into the health and diversity of our ecosystems.

Have you seen a ringed barn owl?

If you have seen a barn owl with a ring on be sure to get in touch. Reporting resightings of ringed barn owls is incredibly valuable for monitoring their longevity and movement patterns within the local area. Although it’s always sad to find a deceased barn owl, it’s important to check if it has a ring. Tragically, road traffic accidents (RTAs) are one of the most common ways we gather resighting data on barn owls, so if it is appropriate and safe to do so, we ask if you see a deceased barn owl near a road, to check for rings. This information will still play a crucial role in guiding future conservation efforts and ensuring the continued protection of these incredible birds.

Do you have a barn owl box or know of any suitable locations in North Cornwall?

Additionally, if you or someone you know has a suitable location for barn owls, or has a barn owl box then let us know! We are always keen to get as much data as we can on barn owls in our local area and are always looking for more boxes to monitor.

Finally, we want to extend a huge thank you to all the landowners and recorders who have supported our efforts to monitor barn owls this year! Your cooperation has been instrumental in making this season such a success. We’re already looking forward to comparing these results with next year’s findings and continuing our work to protect these remarkable birds.

Licensing

As a Schedule 1 protected species, barn owls require a special license to disturb them during the breeding season. The North Cornwall Bird Ringing Group holds all necessary licenses to ensure this work is conducted responsibly. Research shows no adverse effects from ringing barn owl chicks. The process is quick, done during daylight hours, which minimises disturbance to adults and chicks alike.