Presentation on theme: "Feathers and Topography. Feathers Origin: – Originally thought to have evolved from scales – Now thought to be novel structures Composed of beta-keratins."— Presentation transcript:
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
Functions of Feathers Protection Insulation Flight Visual Communication Modified for more A group of crows is known as a murder.
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://thelongestlistofthelongeststuffatthelongestd omainnameatlonglast.com/images/bird1.JPG
Preening Uropygial gland – a.k.a. - preen gland – produces oil (waxes, fatty acids, fat & H 2 0) – located on rump at base of tail – present in most birds – Usually larger in waterbirds
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
Molt Replacement of all or part of the plumage Plumage changes seasonally and with age Energetically taxing Replace damaged feathers, breeding purposes http://www.windoverwings.com/images/isis01.jpg
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.
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