What identification tip is crucial for birders observing single, highly monomorphic species like the Blue-necked Tanager?

Answer

Never rely on minute structural differences like bill length for sexing.

When dealing with species where sexes look very similar based on plumage, observers should refrain from attempting to distinguish them based on small physical attributes such as bill size or posture.

What identification tip is crucial for birders observing single, highly monomorphic species like the Blue-necked Tanager?
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