Feathers

keel bone

• important for flight muscles

• scapula looking abdonmen bone

feathers are skin structures

• provide insulation, aerodynamic for flight, color for communication and camouflage

• modified feathers

  • swimming, sound production, hear, protection, cleanliness, water repellency, water transport, tactile sensation, support

beta-kertain

• fibrous protein polymer

• unique to reptiles and birds

• makes up feathers

contour feather

• long central shaft

  • calmus and rachis

• broad flat vane on either side

calamus

anchors feather in follicle below skin surface

rachis

supports vein

barbs

• lateral branches off of rachis

• primary elements to the vane

• ramus

• barbs and barbules form an interlocking but flexible planer surface

ramus

• barbuels 

• tapered central axis with smaller barbules projecting from both sides

• barbules consist of a series of single cells linked end to end

• can be simple or have projections

  • barbicels

  • hooklike

grading contour feathers

• hidden, fluffy basal part

  • insulation

• exposed cohesive outer part

  • variety of functions

• difference?

  • the lack of barbules towards the base

vaned feathers

• most conspicuous

• smaller contour feathers

• flight feathers

• smooth overlapping arrangement

  • reduces turbulence

wing feathers componants

remiges, coverts

remiges

• large, stuff, pennaceous

• primaries

• secondaries

reminges - primaries

• outer, distal feathers

• forward thrust

• vane location is asymmetrical

• most birds have 10 primaires

• flight efficiency is related to primary structure

• next to 0 modifications

remiges - secondaries

• inner, proximal

  • closer to the body of the bird

• vane location is symmetrical

• 10-19, 40 in albatross

• major structural modifications are more prevalent 

coverts

• overlap remiges 

  • reduces drag

• covering gaps between feather

tail feathers - rectrices

• turning

• symmetrical vane location

• 12 rectrices

  • 6L and 6R

• essential feathers

  • deck feathers

  • central feathers

• major modifications more prevalent

down feathers

• soft, fluffy

• thermal insulation

• lack rachis

• trap air next to skin

• semiplumes

• filoplumes

• bristles

• powder downs

down feathers - semiplimes

• intermediate structures between down and contour feathers

  • enhance insulation

  • fill out aerodynamic contours of body plumage

  • courtship ornaments

down feathers - filoplumes

• hairlike

• monitor movement and position of adjacent vaned feathers

  • allows them to hover in the air during hunting

• distributed throughout plumage

• numerous near mechanically active areas

  • flight feathers

    • 8-12 filoplumes each

    • at the base of the feathers

• consists of a fine rachis that thickens distally

  • ends in terminal tuft of barbs w/ barbules 

down feathers - bristles

• specialized feathers with sensory and protective functions

• stiff tapered rachis

  • few basal barbs

• on heads of birds

• raptor

  • simplified so that they’re easier to clean

• Also occur as eyelashes in rheas, cuckoos- nostril covering in woodpeckers, jays, crows- around mouth in most aerial insect-eating birds for sensory information 

down feathers - powder downs

• produce dust-like keratin 1 micrometer in diameter

• dispersed throughout feather coat

• found in herons, cockatoos 

• disputed in function

  • waterproofing?

  • Parasite prevention?

feather growth

• feathers are dead structures

  • after fully grown

    • cannot change color or form

    • can fade or be abrated 

  • mechanisms for damage repair

    • replace the feather