"walking stick" bird shoes
prolonged support on flat surfaces, especially for some types of feet, cause discomfort and injury.
these shoes, designed for anisodactyl species, help facilitate the natural flexion of perching species' joints, and work in tandem with their tendon locking mechanism.
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Два https://www.weasyl.com/~kifu
Спасибо Ебучему Сергалу за ссылки.