HawkTalk Issue 92 Winter 2022

14

HAWKTALK WINTER 2022 ISSUE 92

An update from our 2021 Marion Paviour Award Winner In 2018, we introduced the Marion Paviour Award with the goal to further research into the conservation of birds of prey. Each year, we give this award to one exceptional early-career researcher for a project working towards this goal.

We were thrilled to have Jaime Carlino as the award winner in 2021, for her work monitoring Barn Owls in Napa Valley, California. Jaime is studying where Barn Owls prefer to nest, how healthy they are and what effect this has on how successfully they reproduce. This work is particularly fascinating for us, as it aligns with our British conservation work providing nest boxes for owls. Jaime tells us more: “During our 2022 field season, I assisted my team in monitoring around 300 nest boxes for Barn Owl occupancy. During these visits, we checked the nest boxes for an incubating or brooding female, the presence of Barn Owl eggs, and/or the presence of Barn Owl nestlings. We revisited the occupied boxes to measure the owls’ reproductive success, which is determined by counting the number of offspring that reach an age where they start to leave the nest box, also known as ‘fledging’. This breeding season was our lowest year of occupancy in the 8 years of our ongoing work in Napa Valley, California, with 22 percent of boxes being occupied. The average number of fledglings from 54 nests was 4.13. This is slightly higher than the average number of fledglings in 2021, which was 4.02. In addition to fieldwork, I have also made progress with data analysis. To address my research questions, I developed an updated model of Barn Owl habitat preferences in Napa Valley, California. Results of this model indicate that Barn Owls in Napa Valley, California prefer wooden boxes that are on taller poles and have greater box height dimensions.

They also prefer boxes with more grasslands and oak savannas around them, while boxes with more forest around them were avoided. These results are consistent with previous models of habitat preferences developed by past students. However, based on our ongoing research on Barn Owl habitat preferences in other regions of California, these results and preferences are not necessarily the same in other regions and crop types. In relation to reproductive success, I found a positive relationship between reproductive success and the predicted probability of nest box occupancy, with boxes that have higher probabilities of occupancy also having higher reproductive success. There is also a positive relationship between observed reproductive success and reproductive success predicted by our model of habitat preferences. This means, our model’s predictions about which habitat features Barn Owls prefer was correct, and this is shown by the higher observed reproductive success in those areas with the preferred habitat types. I look forward to moving forward with more data analysis and thesis writing in preparation for academic conferences and my thesis defense this fall.” If you would like to stay up to date with what Jaime and the research team is up to, you can follow @calpolyhum. barnowls on Instagram and Cal Poly Humboldt Barn Owls (@barnowlHSU) on Facebook.