When a rehabilitated pelican is released back into the wild after contamination in an oil spill, what happens next? Does it survive? Where does it go? These are the critical questions driving researcher and principal investigator Deborah Jaques of Pacific Eco Logic. In partnership with the Oiled Wildlife Care Network (OWCN), Pelican Science, and a host of collaborators across the U.S. and Mexico, Jaques and her Co-Investigators Amelia DuVall and Tammy Russell are tracking the movements and survival of California Brown Pelicans, beginning with pelicans that have undergone rehabilitation for various reasons.
Tammy and Amelia, with radio receivers in hand, are actively tracking HybirdTag'd pelicans while the SensorStations along the California Coast receive pings from pelicans roosting on the breakwater.
Did you know that rehabilitating just one pelican can cost upwards of $1,500? With such a significant investment in each bird's recovery, understanding their post-release success is essential for evaluating the effectiveness of rehabilitation programs and prioritizing conservation efforts.
Pictured here is Deborah sliding the 'latch' onto the HybridTag leg band to lock it in place.
A New Approach to Tracking Pelicans
Historically, tracking Brown Pelicans required bulky, backpack-style GPS transmitters. While effective, these devices could potentially affect the birds' behavior—something Jaques and her team were determined to avoid. Traditional leg bands require in-person resightings, which is impractical for tracking wide-ranging seabirds.
Enter Cellular Tracking Technologies (CTT), who developed the innovative custom version of the HybridTag: a solar-rechargeable radio transmitter embedded into a leg band which was specifically designed for Brown Pelicans for this study. Jaques purchased the prototype HybridTag leg bands and, through field use and feedback, contributed valuable input that helped refine their performance for pelican tracking. This groundbreaking form factor allows researchers to track pelicans without affecting their natural behavior. The data is collected via the Motus Wildlife Tracking System, a program of Birds Canada that encompasses a growing global network of automated radio telemetry stations.
Since the initial pilot in 2021, use of the HybridTag design has undergone several refinements, including auxiliary color bands for easier field identification, a gluing protocol to improve tag longevity, and resizing to better fit smaller female pelicans. These improvements have paid off: by the end of 2024, all 22 tagged pelicans had been successfully detected by Motus towers, with a striking 86% monthly detection probability.
The HybridTag leg band is situated so the solar panel faces out, giving it more opportunity to charge the rechargeable battery.
What We’re Learning
The research has begun to illuminate what happens to pelicans after release. Early analysis from the Motus Phase II report reveals three broad movement patterns among tagged birds: some follow typical migratory routes, others remain largely stationary, and a few venture far afield. These behavioral insights are helping researchers understand habitat use and travel strategies across seasons.
Additionally, preliminary survival modeling suggests that environmental factors, such as oceanographic conditions and prey availability, may influence survival—especially for juveniles. For instance, survival rates dipped during periods when indicators of poor foraging conditions, like elevated Pacific Decadal Oscillation values, were present. This kind of data is critical for anticipating how climate and marine ecosystem changes may affect pelican populations.
A picture of "Georgine (H3)" with its HybridTag leg band.
Collaboration Is Key
This effort has grown into a truly international collaboration. In addition to the OWCN and CTT, partners include field teams from International Bird Rescue, Pacific Wildlife Care, Wetlands and Wildlife Care Center, the U.S. Geological Survey, and Mexico’s Comisión Nacional de Áreas Naturales Protegidas. Each partner has played a vital role in capturing, rehabilitating, tagging, releasing, and tracking these charismatic seabirds.
Kyra Mills, Deputy Director of Field Operations at OWCN, emphasizes the importance of this work: “Tracking post-release survival and breeding success justifies the entire existence of oiled wildlife response.”
A release in progress!
Looking Ahead
As more data roll in and additional pelicans are tagged in 2025 and beyond, Jaques and her Co-Investigators Amelia DuVall and Tammy Russell aim to explore deeper questions about pelican movement ecology. These include the degree of connectivity between U.S. and Mexican populations, sex and age-based differences in survival, and the impact of environmental variability on foraging and migration.
For now, the Motus Phase II report offers a promising sign: rehabilitated pelicans are not only surviving, but offering researchers an unprecedented look at their post-release journeys.
The above map shows the movement from Pelican H7 from July 2024 through April 2025.
These findings are based on the Motus Phase II Final Report (Jaques et al., 2025), a summary of the first year of data in an ongoing three-year study.