Least Bell's Vireos and Southwestern Willow Flycatchers at the San Luis Rey Flood Risk Management Project Area in San Diego County, California: Breeding Activities and Habitat Use—2023 Annual Report

Science Support for Recovery of Southwestern Willow Flycatcher (Empidonax traillii extimus) on Conserved Lands in San Diego County 

Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California—2022 Annual Report

Least Bell's Vireos and Southwestern Willow Flycatchers at the San Luis Rey Flood Risk Management Project Area in San Diego County, California: Breeding Activities and Habitat Use—2022 Annual Report

Distribution, Abundance, and Breeding Activities of Southwestern Willow Flycatchers (Empidonax traillii extimus) at Select Locations on the San Luis Rey River, San Diego County, California—2024 Data Summary

Distribution and Abundance of Southwestern Willow Flycatchers (Empidonax traillii extimus) on the Upper San Luis Rey River, San Diego County, California—2023 Data Summary

Evidence of honest signalling in a suboscine bird: Southwestern willow flycatcher song frequency is positively related to apparent reproductive success

Biocontrol & Threatened and Endangered Species Amanda Stahlke1*

Applying Satellite-based Habitat Models to Inform Riparian Habitat Restoration and Management Actions for Two Listed Riparian Species, the Southwestern Willow Flycatcher and the Yellow-billed Cuckoo 

  James Hatten1, Jennifer Holmes2, and Matthew Johnson3* 

This chapter from The Codex of the Endangered Species Act, Volume II: The Next Fifty Years describes how genetic information is used to inform decision-making for the Endangered Species Act. In one section of this chapter (page 4 of the PDF, page 162 of the book), the use of genomics to differentiate between subspecies of willow flycatcher (Empidonax traillii) is described.