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

Functions of Feathers

• Protection• Insulation• Flight• Visual Communication• Modified for more

A group of crows is known as a murder.

Feather Structure

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

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

Topography

• 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.