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Feathers and Topography. Feathers. Origin: Originally thought to have evolved from scales Now thought to be novel structures Composed of beta-keratins Weigh 2-3 times the skeleton. http://www.themodernapprentice.com/feathers.htm. A group of crows is known as a murder.
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Feathers • Origin: • Originally thought to have evolved from scales • Now thought to be novel structures • Composed of beta-keratins • Weigh 2-3 times the skeleton http://www.themodernapprentice.com/feathers.htm
A group of crows is known as a murder. Functions of Feathers • Protection • Insulation • Flight • Visual Communication • Modified for more
Feather Types • Contour and Flight • Down (plumules) • Semiplumes • Filoplumes • Bristles
Feather Maintenence • Preening • Bathing • Dusting • Sunning • Anting • Chemical Defenses The smallest bird in the world: Bee Hummingbird http://thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com/images/bird1.JPG
Preening • Uropygial gland • a.k.a. - preen gland • produces oil (waxes, fatty acids, fat & H20) • located on rump at base of tail • present in most birds • Usually larger in waterbirds
Oil from uropygial gland • Cleans feathers • Preserves feather moistness • Preserves flexibility • Essential ??? • Maintains structural integrity of feather • Allopreening - mutual preening by conspecifics • widespread, 43+ families • maintains pair bonds
More Maintenence • Bathing • Dusting • similar to bathing • Sunning • also helps with thermoregulation • Anting • treat feathers with live ants • widespread activity • studies have shown higher levels of dead ectoparasites
Chemical Defenses • Not known in birds until 1992 • 3 species of shrike-thrushes (New Guinea forest birds) • Skin feathers produce deadly neurotoxin http://www.camacdonald.com/birding/LittleShrikethrush(SM).jpg
Feather Color • Protection from sun • Heat absorption • Escape from Predation • cryptic coloration • countershading • Mating • Chemical and Structural The most abundant bird? Possibly the Red-billed Quelea (Africa). 10 billion strong. (Cornell Lab of Ornithology)
Feather Growth • Once fully grown, feather is dead structure • Grow from follicles in skin • Follicle collar- ring of feather stem cells (horizontal or tilted) • Old feather pushed out as new feather grows • Begins as tube • Outer layer: sheath • Intermediate layer: barb ridges
Feather Growth • As feather emerges, cells filled with beta-keratin • Sheath cracks off, feather uncoils • Feather connected to blood supply as growing, living cells and blood vessels reabsorbed by follicle • Calamus remains in follicle, held by muscles and friction • See pages 89-91 in Gill
Feather Tracts • Feather tracts • Feathers grouped into 9 tracts • Spaces between feather tracts are Apteria • Brood patch is specialized apteria • Penguins lack apteria • Diagram in packet
http://www.windoverwings.com/images/isis01.jpg Molt • Replacement of all or part of the plumage • Plumage changes seasonally and with age • Energetically taxing • Replace damaged feathers, breeding purposes
What Influences Molt? • Weather • Behavioral requirements • migration • reproduction • Geographic location • tropics vs. temperate • Food availability
Molting Pattern for Typical Passerine • November - February • prealternate molt • March - May • Migration to breeding grounds • alternate plumage • June - July • Breeding period (egg laying / rearing) • alternate plumage
Molting Pattern for Typical Passerine • July - August • prebasic molt • August - November • Migration to wintering grounds • basic plumage
For more details on topography, look in front of field guide. • Field marks to look for when identifying birds • Eye line • Supercilium line (line above eye) • Malar streaks • Upper wing coverts • Many more………… A group of flamingoes is know as a flamboyance.
Terminology • See handout, look for examples in lab • Foot arrangement • Toes • Beak Shapes • Wing Shapes • etc. etc.