California’s Sacramento Valley has lost much of its native riparian and wetland habitats because of anthropogenic land-use change. Efforts to restore habitat have occurred, and bird responses have been primarily studied on public lands, whereas restoration on private lands remains largely understudied. We assessed avian occupancy using passive acoustic monitoring during the breeding season on a private hunting club, comprising a heterogenous mix of rice, managed wetlands, and native riparian forest, in the Central Valley’s Butte Basin, California, USA. In total, we detected 85 bird species. We detected 95% of the known breeding passerines on the property. Using a multi-species occupancy model, we determined occupancy by habitat for 21 of the most common species on the property, which revealed riparian and oak habitat specialists and reflects occupancy patterns documented for other regions in the Central Valley. We found that native riparian strips support greater species richness compared to marsh and rice habitats, with an average of 30 (90% CI: 2–32) passerine species and 13 (90% CI: 11–16) non-passerine species, despite representing 7% of total land cover. These findings can be used to encourage restoration and protection of native riparian habitat as a practice adopted by private landowners interested in maintaining overall avian diversity on their lands. Passive acoustic monitoring proved an effective method to characterize the overall avian community on this 1020 ha property. However, we believe that there is a lower limit of parcel size to allow for enough independent samples and data to be used in occupancy models. Based off our results, using audio recording units at the parcel level yield species diversity results for breeding passerines comparable to traditional avian survey methods and would provide a less invasive, long-term monitoring technique on private properties, particularly for passerines.
Fradet et al. (Thu,) studied this question.