UCD Barn Owl Project

Work from Cal Poly Humboldt Barn Owls team is highlighted in this short video about Barn Owls living on vineyards in Napa, California. 🍇 🦉

Barn Owl Table Manners are Just ... Different | KQED Barn owls swoop down on rodents and swallow them whole – gophers, voles and mice, gone in a few gulps. But how do they keep down all that food? Well, they don’t. In a few stomach-turning steps, they transform the varmints into compact balls of fur and bones known as pellets.

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!

Humboldt State graduate student researchers are making a positive impact on farm sustainability!

California Wine Growers Replace Rodenticide With Raptors - Bay Nature Replacing pesticides with barn owls for rodent control was one of several innovations that marked a new appetite for more environmentally sustainable production in California vineyards.

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!

Implementing a Barn Owl nest box network in agriculture can increase natural pest control on the landscape. If you want to learn more about the logistics of installing and managing Barn Owl nest boxes please read our new Quick Guide!

This year we are investigating how nest box temperature and rodenticide exposure impact breeding Barn Owls. Our findings will help inform pest control strategies and promote healthy Barn Owl populations in the future. Photo credit: Coco Yeung

Anticoagulant rodenticides can enter the food web where they are dangerous to owls and other predators. To learn more about how anticoagulants are impacting Barred and Spotted owls in our northern CA forests see below.

Danny Hofstadter (University of Wisconsin, Madison) gave a wonderful presentation to RATS today on barred owls and anticoagulants in Northern Calilfornia. We now have a recording of his talk on our website: https://www.raptorsarethesolution.org/wp-content/uploads/2021/03/AR_Exposure.mp4
Barred owl photo by Walter Keenan

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 😳 🤯

Surprise! While most of our pairs are just laying eggs now, this family has 3-4 week old nestlings!

Happy Owlintine’s Day 💗