Seasonal abundance and habitat associations of wandering cats and birds in a temperate zone biodiversity hotspot

The interaction between birds and wandering domestic cats is an ongoing challenge for both wildlife conservation and cat welfare, particularly in regions where high avian diversity overlaps with dense human development and wandering cats. I examined the abundance, richness and community structure of birds and the abundance of wandering domestic cats (Felis catus), in the temperate biodiversity hotspot of the south Okanagan Valley, British Columbia, Canada, between Okanagan Falls and Osoyoos, across an entire annual period. I did this by pairing point counts and photos from trail cameras from 123 locations across five seasonal periods between March 2022 and March 2023, assessing the habitat associations of birds and cats across a variety of land use types, including urban, peri-urban, agricultural, and natural. I conducted a total of 2380 point counts and used hierarchical modelling and unconstrained ordination to examine bird abundance and species richness, and community composition, respectively. My results revealed distinct seasonal patterns of bird abundance and richness with these metrics being the highest during spring migration and the breeding season. Urbanization and human development impacted the distribution of birds year-round, especially in the non-breeding seasons when a large diversity of species used urban areas. Using the same locations as the point counts, but shifting cameras every 28 days, I examined local abundance of wandering cats. I showed that wandering cats were found in high abundances in urban habitats year-round but overall had the highest abundances during the early winter, spring, and summer. Wandering cats were detected at 100% of peri-urban sites, 97% of urban sites, 65% of agricultural sites and 42% of natural sites. I estimated an annual average of 6,557 wandering cats within the study area with up to 82% of them being unowned cats, equating to one cat for every two to three people. Overall, I demonstrate the importance of identifying where birds are and what habitats they are using across the entire year and not only during distinct periods within the annual cycle (e.g. breeding). The high numbers of wandering cats, combined with the diversity of birds and other wildlife, suggests that cats likely have significant impacts on birds and other wildlife year-round in the study region and likely elsewhere. In the south Okanagan Valley, management actions such as outreach initiatives should take a seasonal and habitat-based approach. Outreach should focus on encouraging urban residents to keep their cats indoors during the winter because many species move into urban areas at this time. Resident in peri-urban and agricultural habitats should be encouraged or incentivised to spay and neuter cats on their property and keep cats inside during spring, summer, and fall when high cat numbers overlap with high bird abundance and richness. Given the high abundance and richness of birds along with the highest currently reported abundances of wandering cats per capita, these results stress the urgent need for collaborative efforts among municipalities, stakeholders, and residents to mitigate the ecological impact of wandering cats and help preserve the biodiversity of this unique region.