Semiplumes definitions

Semiplumes

in between down and contour feathers, with a large rachis and loose downy vanes. They enhance insulation.
Found on http://www.sialis.org/glossary.htm

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semiplumes

Feathers that occur in a continuum of forms between down and contour feathers. Located at the edges of the contour feather tracts, semiplumes provide insulation and help to maintain the bird's streamlined shape.
Found on https://academy.allaboutbirds.org/bird-academys-a-to-z-glossary-of-bird-ter

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