Setophaga townsendi x virens
Status: Accidental in fall.
Record: One was photographed at Wildcat Hills Nature Center, Scotts Bluff Co 31 Aug 2018 (https://ebird.org/checklist/S48275283).
Comments: The Nebraska record was pointed out to us by Jon King; originally identified as a Townsend’s Warbler, hybrid characters can be detected in the photo, including increased black in the face and a yellow breast wash.
This hybrid is well known as a result of recent studies by Toews et al (2011), discussed by Mlodinow et al (2014) with respect to two such hybrids found in Colorado. Toews et al (2011) found “surprisingly extensive” hybridization, some 38% of individuals sample within the hybrid zone in the Rocky Mountains of British Columbia. It seems quite reasonable to assume that such hybrids would migrate south in fall along the east edge of the Rocky Mountains (Mlodinow et al 2014; Jon King, pers. comm.).
Acknowledgements: Photograph (top) of a Townsend’s x Black-throated Green Warbler (hybrid) at Wildcat Hills Nature Center, Scotts Bluff Co 31 Aug 2018 by Mark A. Brogie.
Mlodinow, S.G., G. Walbeck, and D.A. Leatherman. 2014. Two recent records of apparent Black-throated Green Warbler × Townsend’s Warbler in Colorado. Colorado Birds 48: 102-106.
Toews, D.L.P., A. Brelsford, and D.E. Irwin. 2011. Hybridization between Townsend’s Dendroica townsendi and black‐throated green warblers D. virens in an avian suture zone. https://doi.org/10.1111/j.1600-048X.2011.05360.x.
Silcock, W.R., and J.G. Jorgensen. 2021. Townsend’s x Black-throated Green Warbler (hybrid) (Setophaga townsendi x virens). In Birds of Nebraska — Online. www.BirdsofNebraska.org
Updated 15 Mar 2021