Lecture_12-1 - Reasons for molt: 1. Replacement of worn...

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Lecture 12 Notes Birds have many different types of feathers: Filoplume – bare rachis with tuft at the top – associated with flight feathers – many nerve endings Bristle – bare rachis – functional equivalent of eyelash or whisker Semiplume – have a rachis - short fluffy feather functions as insulation Down – no rachis – short fluffy feathers that function as insulation Contour feathers – outer feathers covering the body 3 types – flight feathers (remiges), tail feathers (rectrices), and body feathers Contour feathers have structural components: Microstructure – barbs which include the ramus, barbules, and hooklets Feather color can vary based on: Sex Age Season Molt = the loss and regrowth (replacement) of feathers
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Unformatted text preview: Reasons for molt: 1. Replacement of worn feathers 2. Change the color and shape of feathers Molting cycles: Prejuvenal molt 1 st molt of a birds life natal down replaced by juvenal plumage Prebasic molt juvenal or alternate plumage replaced with non-breeding plumage. This is always a complete molt (all feathers). Usually occurs in winter Prealternate molt basic plumage replaced with breeding plumage. Usually occurs in summer. Thyroid hormones are important for all three types of molt. Molt Patterns: 1. Complete prebasic Complete prealternate (rare) 2. Complete prebasic Partial prealternate 3. Complete prebasic No prealternate...
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Lecture_12-1 - Reasons for molt: 1. Replacement of worn...

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