First Definitive Records of Hermit Thrush and Wilson’s Warbler Subspecies for Nebraska

Authors

• Stephen J. Brenner, National Audubon Society–Great Plains
• Joel G. Jorgensen, Nebraska Game and Parks Commission

Date of this Version

12-2025

Document Type

Article

Citation

Nebraska Bird Review, volume 93, number 4, December 2025, pp. 179–185

Comments

Published by the Nebraska Ornithologists’ Union, Inc.

Abstract

During the fall of 2025, we initiated a pilot migratory bird-banding project in the Nebraska Panhandle. While the project’s goals included examining species composition, volume, and body condition of migratory birds at the western edge of the state compared to the eastern edge of the state, we also used this project to document the occurrence of subspecies and species which are very challenging or impossible to identify through field observation. Here, we report on the first definitive records of two subspecies in Nebraska.

On 16 September 2025, SJB banded an adult male Wilson’s Warbler (Cardellina pusilla) that was determined to be of the subspecies C.p. chryseola based on wing, tail, and crown measurements and supported by plumage features, namely an extensive amount of orange wash to the lores, supercilium, and forehead. The wing measured 57 mm, the tail measured 49 mm, and the black cap measured 20 mm. The black crown measurement in particular is beyond the range of the other two Wilson’s Warbler subspecies (C.p. pusilla and C.p. pileolata). A second adult male Wilson’s Warbler banded on 18 September also had an orange wash to the lores, but its other measurements were nearly definitive for reported C.p. pileolata range, and the orange wash was not as extensive as the bird banded on the 16th. This is the first known banding record and reported record of this taxon for Nebraska, and one of the most eastern records for the continent.

On the same day, SJB banded a hatch-year Hermit Thrush (Catharus guttatus) that was determined to be of the subspecies C.g. auduboni. This identification was based on size and supported by plumage features. The wing measured 100 mm, which is above reported wing chord lengths for the other Hermit Thrush subspecies and diagnostic for identification. The overall plumage included a duller red-brown tail contrasting with a grayish-brown back, dull gray wash to flanks, and lacking bold rusty tones to wing coverts and primary edging, which are all marks typical for C.g. auduboni. This is the first confirmed mensural record for this taxon in the state, as no definitive specimen or other banding record exists. However, this taxon has long been suspected to occur in the state based on nearby breeding geography and multiple sight records, with ~10 reports since 2019. Three additional Hermit Thrush were banded at this site later in the season, and all were definitively not C.g. auduboni based on measurements and plumage but were equivocal as to positive identification of subspecies.