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.

A look at the evolutionary response to climate change in the endangered southwestern willow flycatcher (Empidonax traillii extimus) using whole-genome comparisons between historic and modern specimens from California. While introgression led genomes of neighboring E. traillii extimus populations (California and Arizona) to become more similar, the specific loci linked to climate shifted in a way consistent with climate adaptation rather than becoming more similar to those of neighboring populations.

A look at the potential for  southwestern willow flycatcher (Empidonax traillii extimus) adaptations to rising temperatures from an ecological genomics perspective. Compared to other willow flycatcher populations results indicate small, fragmented populations of the southwestern willow flycatcher will have to adapt most to keep pace with climate change.

Habitat factsheets and scorecards describe the habitat needs and behaviors of species of interest in the Colorado State Wildlife Action Plan. This particular document is for Southwestern Willow Flycatcher. These habitat details and score cards can be used to analyze current habitat conditions and potential for improvement.