How is the transition area between the male Wood Duck's chest and flanks described?

Answer

The deep, purplish-chestnut chest meets buffy-yellow or tan flanks, separated by a noticeable black band

The chest plumage of the male Wood Duck is characterized by a deep, rich purplish-chestnut color generously dotted with small white spots. This intense coloration does not simply transition into the lower body plumage but is distinctly demarcated. Moving outward toward the sides, the plumage shifts to buffy-yellow or tan hues, defining the flanks. The crucial visual element separating these two areas is a noticeable black band running across the bird, providing a sharp line of contrast between the upper chest coloration and the flank coloration.

How is the transition area between the male Wood Duck's chest and flanks described?
birdcharacteristicduckPlumage