What key wing feature aids in definitively identifying the Western Tanager versus the Scarlet Tanager?

Answer

Two prominent white or yellowish wing bars

The presence of two prominent white or yellowish wing bars on the black wings is essential for definitive identification, as it separates the Western Tanager from the Scarlet Tanager, which has solid black wings.

What key wing feature aids in definitively identifying the Western Tanager versus the Scarlet Tanager?
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