Vermivora chrysoptera x VERMIVORA cyanoptera Status: Rare casual spring and fall migrant east. Documentation: Brewster’s Warbler: photograph, 18 May 2020 Madison Co (Brogie, in gallery). Taxonomy: This species and Blue-winged Warbler V. cyanoptera hybridize frequently and produce fertile hybrids; their genomes are 99.97% identical, with plumage genes accounting for the difference (Toews et al 2016). […]