by Sarah Kendrick, US Fish and Wildlife Service, Migratory Bird Biologist

CAS donated funds for the Motus tracking program as referenced in this article that was previously printed in the 2025 Missouri Natural Areas Newsletter. To see the article with images and other links, visit the original publication in the NA Newsletter in link above. 

In 2024, a multi-national group of bird-conservation partners across the hemisphere initiated a massive research project to track the survival and migration of Wood Thrush across the breeding and nonbreeding ranges. This effort occurred in 2024-2025 to target conservation efforts for the species – an important forest-breeding bird. (Fig 1)

Between May and July 2025, with Colombian bird-conservation organization SELVA, I coordinated over 60 partners to deploy over 990 Motus Wildlife Tracking System tags on Wood Thrush in 27 U.S. states and Ontario across the species’ breeding range. SELVA coordinated the tag deployment of over 140 more Motus tags in five countries of the species’ nonbreeding range this past winter, making our effort the largest Motus project to date.

The Wood Thrush (Hylocichla mustelina) is a medium-sized songbird of Eastern deciduous forests known for its flute-like, ethereal, ee-oh-lay song. The Wood Thrush is a long-distance Neotropical migrant, meaning it spends over half the year in tropical forest from Mexico to Panama. This thrush acts as a flagship species for full annual cycle conservation work in the Neotropics because they require a mid-elevation forest structure on nonbreeding grounds that is also needed by many other forest-breeding migratory songbirds. Full annual cycle conservation means working to identify and address threats that migratory birds face through all stages of their year, including breeding stage, migration stages, or nonbreeding stage.

With over 1,100 tags deployed on the species over its full range, we will better understand Wood Thrush migratory connections, routes, timing and survival across the full annual cycle to inform conservation action. The Wood Thrush is a priority species for conservation in 25 states and holds threatened status in Canada. Improving our understanding of the ecology of this species’ full annual cycle is essential to better understand conservation needs throughout its range and to improve the design of targeted habitat management actions. The hemispheric Motus-tagging research and conservation project will help us to better understand migratory connections, routes, timing and survival across their full annual cycle.

In spring 2023, I approached state wildlife agencies via the Nongame Bird Technical Sections of the Mississippi and Atlantic Flyway Councils to ask if they were interested in being part of a large-scale research study on Wood Thrush. The project goals were to tag the species with Motus tags across their breeding range in the eastern U.S., in partnership with SELVA, who would coordinate Motus-tagging in Mexico, Belize, Guatemala, Honduras, Nicaragua and Costa Rica. The pitch was that, if states or organizations could commit the funds for 25 tags and coordinate the deployment of those tags on Wood Thrush in their state with permitted taggers, I would handle the coordination and logistics of the project, and we could do something at an unprecedented scale to learn a lot about the species together. To my surprise, many states and federal agencies and other organizations signed onto the project to participate! Mass planning commenced.

Our partner SELVA and I wrote a common (and required) project protocol to ensure that all project partners were using the same field methods, Motus tags, attachment harnesses and bird-handling permitting process.

The Motus tags deployed on Wood Thrush have batteries that last nearly 1.5 years, allowing us to gather up to three migratory seasons of data and allow us to examine inter-annual survival, which can be difficult to study in migratory species.

Many aspects of this project are providing us a positive proof of concept, including its scope and scale, and unique funding streams. A number of private, in-state funding streams are helping numerous states fund their project’s Motus tags or field work, making this massive project largely a grassroots-funded effort. Multiple birding groups in Missouri, including the Missouri Birding Society, Burroughs Audubon Society, Columbia Audubon Society and other private donors funded Missouri’s Motus tags and a Motus station for the project.

Data have been pouring in since May 2024 when tagging began. Field work wrapped up in summer 2025, but another year’s worth of data remains to be collected from nearly 500 Wood Thrush tagged this past summer across their breeding range. After that, we hope our project’s analysis will give us new insights into Wood Thrush survival and migration, allowing us to better deliver conservation for this iconic Eastern-forest bird.