Species Conservation

Jump to: Spotted Owl – Pinyon Jay – Yosemite toad – Marbled Murrelet – Gray Wolf

See Collaborative Projects for more species-oriented work

Spotted Owl

I began working with Spotted Owls in 2016 as a PhD student with Dr. Zach Peery at the University of Wisconsin-Madison. Our collaboration – and that project – have continued to this day, and the footprint of our work has grown substantially, encompassing the entirety of the Spotted Owl’s range in California.

Sierra Nevada

The focus of my dissertation was the development of a landscape-scale acoustic monitoring program in the northern Sierra Nevada. Until then, Spotted Owl monitoring had been conducted small study areas, albeit with very detailed mark-recapture methods. I implemented a passive acoustic survey approach that allowed us to triple the spatial coverage of the nearest conventional study. This broad spatial coverage was essential to understanding the progression of the ongoing invasion of Barred Owls, as well as to allow for more robust inferences about the spotted owl population.

The first major finding of the project was that the Barred Owl population was growing rapidly in the northern Sierra Nevada. All available evidence suggested that the establishment of Barred Owls in the Sierra Nevada would doom the California Spotted Owl in the core of its range. A unique coalition of academic, agency, and industry partners came together to implement an experimental removal of Barred Owls, which ultimately eradicated them from the Sierra Nevada and enabled a nearly immediate recovery of the Spotted Owl.

In the Sierra Nevada, Spotted Owl conservation has pivoted (back) to an attempt to understand how the threat of long-term habitat loss driven by megafires can be counteracted by forest management that risks incurring short-term habitat degradation. Continual refinement of the acoustic monitoring program is central to this effort because accurately assessing where owls are and are not in relation to fire and forest management is essential to understanding – and managing – how the population is changing across time and space.

Southern California

The Southern California-Coastal Designated Population Segment (DPS) of the California subspecies of the Spotted Owl (yes, that’s a mouthful) has declined by over 50% over the last 30 years. It faces a greater risk of regional extirpation than the Sierra Nevada DPS of the California subspecies, yet little is known about the owl outside of several long-term monitoring areas, which challenges both owl conservation and the implementation of urgently needed forest restoration to reduce the risk of large, severe fires.

My group has led the development of the first Southern California-wide Spotted Owl monitoring program, which began in the spring of 2024, and immediately located owls that were either previously unknown to local biologists or hadn’t been surveyed in many years. We overhauled the design in the offseason, and the 2025 season yielded even more birds.

Northern California

Barred Owls remain an urgent threat to the northern subspecies of the Spotted Owl, and I am collaborating with the Zach Peery’s group in their work in California’s coastal redwood region to understand how we can effectively monitor – and control – the Barred Owl population in what appears to be the last stronghold of the northern Spotted Owl.

Representative Publications
  1. Gustafson, ML, K McGinn, JA Heys, SC Sawyer, and CM Wood. 2025. Rapid implementation and adaptive design of a large-scale monitoring program for a declining species. Biological Conservation 311: 111442.
  2. Kelly, KG, CM Wood, KA McGinn, HA Kramer, SC Sawyer, SA Whitmore, DS Reid, S Kahl, A Reiss, J Eiseman, W Berigan, JJ Keane, P Shaklee, L Gallagher, H Klinck, RJ Gutiérrez, and MZ Peery. Estimating population size for California spotted owls and barred owls across the Sierra Nevada with bioacoustics. Ecological Indicators 154: 110851.
  3. Watson, WA, CM Wood, KG Kelly, DF Hofstadter, KF Kryshak, CJ Zulla, V O’Rourke, JJ Keane, RJ Gutiérrez, and MZ Peery. 2023. Passive acoustic indicates Barred Owls are established in northern coastal California and management intervention is warranted. Ornithological Applications duad017.
  4. Hofstadter, DF, NF Kryshak, CM Wood, BP Dotters, KN Roberts, KG Kelly, JJ Keane, SC Sawyer, PA Shaklee, HA Kramer, RJ Gutiérrez, and MZ Peery. 2022. Arresting the spread of invasive species in continental systems. Frontiers in Ecology and the Environment. doi: 10.1002/fee.2458.
  5. Reid, D, CM Wood, SA Whitmore, WJ Berigan, JJ Keane, SC Sawyer, PA Shaklee, HA Kramer, KG Kelly, A Reiss, RJ Gutiérrez, H Klinck, MZ Peery. 2021. Noisy neighbors and reticent residents: Distinguishing resident from non-resident individuals to improve passive acoustic monitoring. Global Ecology and Conservation. e01710.
  6. Wood, CM, RJ Gutiérrez, JJ Keane, and MZ Peery. 2020. Early detection of rapid Barred Owl population growth within the range of the California Spotted Owl advises the Precautionary Principle. The Condor 122: 1-10.

Pinyon Jay

The Pinyon Jay has declined by nearly 50% over the last 30 years. Yet its complex use of diverse habitats across the interior west – and prioritization of sagebrush obligate species – has challenged conservation efforts. The U.S. Fish and Wildlife Service is now considering the jay for listing under the Endangered Species Act, so we are collaborating with the Great Basin Bird Observatory to develop scalable survey protocols that the USFWS, U.S. Forest Service, Bureau of Land Management, and other agencies can use to assess populations across the landscape. The jay is highly social species that can form flocks numbering into the hundreds, so we will also be exploring acoustically-based abundance estimation and linkages between pine cone crops and flock size.

We also participate in the Pinyon Jay Working Group, a collaborative effort to coordinate and support conservation research focused on the jay.

Our work with Pinyon Jays is led by postdoc Meghan Beatty.

Yosemite toad

Like many amphibians, the Yosemite toad is declining. Yet the causes have been difficult to diagnose because annual surveys of the adult population are very difficult to conduct. The Yosemite toad breeds immediately after snowmelt in high-elevation meadows in California’s central Sierra Nevada, which means accessing sites when adult toads are most conspicuous is very difficult.

  • In spring 2021, I conducted a pilot study which showed that we can deploy autonomous recording units before the snow melts, retrieve them later in the summer, and then use BirdNET to identify the vocalizations of Yosemite toads, as well as Pacific chorus frogs. I made a short video about that field effort, which helped me obtain a Discovery Expedition Grant from The Explorers Club.
  • In spring 2022, supported by the DEG, I conducted a six-day expedition into the High Sierra to deploy 14 recording units across an area that is only rarely surveyed for the toad. That work was featured briefly on Discovery’s new show “Tales from the Explorers Club”. I also wrote about the project for ‘The Snowboarder’s Journal’.
  • In spring 2025, supported by Patagonia, I conducted another six-day expedition into the High Sierra with professional splitboarders Nick Russell and Forrest Shearer. A multimedia story about that trip will be released in spring 2026….

The ongoing US Forest Service toad monitoring project conducts mark-recapture surveys at a few breeding areas, and the next step is comparing vocalization counts to adult population counts to derive an acoustic-based population index that could be applied more broadly.

Publications
  1. Wood, CM, S Kahl, R Van Horne, and C Brown. Passive acoustic surveys and a novel machine learning tool reveal detailed spatiotemporal variation in the vocal activity of two Anurans. Bioacoustics. doi: 10.1080/09524622.2023.2211544.
  2. Wood, CM, J Champion, C Brown, W Brommelsiek, I Laredo, R Rogers, and P Chaopricha. Challenges and opportunities for bioacoustics in the study of rare species in remote environments. Conservation Science and Practice e12941.

Marble Murrelet

Federally Threatened since 1992 and state Endangered in California (1992), Washington (2016), and Oregon (2021), the Marbled Murrelet is an seabird that nests almost exclusively in old-growth forests along the north Pacific coast of North America. Current survey efforts are limited to time-intensive human surveys; passive acoustic surveys offer a scalable alternative to understanding where this species persists on the landscape. In collaboration with Brian Dotters of Sierra Pacific Industries and Dr. Zach Peery of UW-Madison, we are developing an acoustic survey protocol that can meet or exceed current regulatory standards for murrelet surveys in determining occupancy and nesting status in stands of old-growth forest. This project is led by graduate student Rylie Strasbaugh.

Gray Wolf recolonization of California

In 1924, wolves were extirpated from California. In 2015, the first confirmed wolf returned to the state. As of 2022, according to the California Department of Fish & Wildlife, there were three wolf packs in the state. Information about wolf abundance and dispersal is a critical component to managing the potential conservation conflicts that can arise with the natural return of wolves. Their long-term future will depend in part on understanding pack size and distribution to facilitate co-existence with human communities. We are leveraging passive acoustic monitoring techniques to work with agency partners to support wolf management in California and beyond.

Looking beyond California, wolves are a global touchstone for conservation conflicts. By improving tools for wolf monitoring, we hope to mitigate the intensity of these conflicts and facilitate scalable conservation research for this iconic species.

Partners

UC-Davis, UC-Berkeley, California Department of Fish and Wildlife, U.S. Forest Service

Publications
  1. Sossover*, D, K Burrows*, S Kahl, and CM Wood. Using the BirdNET algorithm to identify wolves, coyotes, and potentially their interactions in a large audio dataset. Mammal Research. https://doi.org/10.1007/s13364-023-00725-y