What physical feature is described as the most defining characteristic of the Hoiho?

Answer

The pale yellow iris encircled by a sweeping band of yellow feathers

The most unmistakable identification mark for the Yellow-Eyed Penguin is centered entirely around its ocular region. It possesses a striking, pale yellow iris, which contrasts sharply with the surrounding plumage. This eye is further framed by a unique feature: a distinct band of yellow feathers that originates above the eye and sweeps gracefully backward toward the nape of the neck. This sweeping arc is often likened to a 'tiara' or 'halo' and is configurationally unique among penguin species, serving as the primary visual identifier for the Hoiho.

What physical feature is described as the most defining characteristic of the Hoiho?
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