Plural of covert; sheltered places, or feathered areas on a bird's wing, or small hidden groups.
From Old French 'couvert,' which is the past participle of 'couvrir' (to cover). A 'covert' is literally something covered or a covered place, and has been used in English since the medieval period.
Bird feathers have wonderful names—a covert is one of the small feathers that covers the base of larger flight feathers, helping birds become aerodynamic. Nature's engineering is hidden in the poetry of these technical terms!
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