Wilson’s Warbler

The six genetically distinct populations of Wilson’s Warbler (Cardellina pusilla) (left map) across the breeding range: Coastal California (yellow), Pacific Northwest (green), Basin Rockies (orange), Western Boreal (purple), California Sierras (pink), and Eastern (red). Individuals sampled on the wintering grounds (right map) were then assigned back to their respective breeding genetic cluster, allowing us to better understand the migratory connectivity of Wilson’s Warbler populations. Genetic clusters are visualized as transparency levels of different colors overlaid upon a base map from Natural Earth (naturalearthdata.com) and clipped to the species breeding range using an eBird shapefile. See below for details of samples used. Wilson’s Warbler Image by © Birds of the World

The Wilson’s Warbler (Cardellina pusilla) breeds in a wide range of habitats across Canada and the United States, but generally prefer alder and willow thickets, and forest edges with a dense understory. As these habitats disappear, population numbers have plummeted, resulting in a decline of over 60% since 1966. With their large breeding and wintering distributions, it has been complicated to understand which Wilson’s Warbler populations are facing the greatest declines.

The Bird Genoscape partnered with multiple collaborators (see below) to develop high-resolution molecular markers to identify breeding populations of Wilson’s Warblers in North America. We scanned the genomes of 408 individuals from 33 sampling locations across the Wilson’s Warbler breeding range to identify population genomic structure. In total, we’ve identified the existence of 6 genetically distinct populations of the Wilson’s Warbler (left image) – Western Boreal (purple), Eastern (red), Basin Rockies (orange), Pacific Northwest (green), California Sierras (pink), and Coastal California (yellow). These 6 populations can serve as the foundation for Wilson’s Warbler conservation and management.

See below for details of samples used.

Read below to learn about our work constructing the Wilson’s Warbler genoscape and how managers can use it to prioritize conservation areas:

Ruegg KC, Harrigan RJ, Saracco JF, Smith TB, and CM Taylor. 2020. A genoscape-network model for conservation prioritization in a migratory bird. Conservation Biology 34: 1482-1491

Ruegg KC, Anderson EC, Harrigan RJ, Paxton KL, Kelly, Moore JF, F. and TB Smith. 2017. Genetic assignment with isotopes and habitat suitability (gaiah), a migratory bird case study. Methods in Ecology and Evolution: 8: 1241-1252

Ruegg KC, Anderson EC, Paxton KL, Apkenas V, Lao S, Siegel RB, DeSante DF, Moore F, and TB Smith. 2014. Mapping migration in a songbird using high-resolution genetic markers. Molecular Ecology 23: 5726-5739