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.
Functions of Feathers
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Protection
Insulation
Flight
Visual Communication
Modified for more
Feather Structure
Feather Types
• Contour and Flight
• Down (plumules)
• Semiplumes
• Filoplumes
• Bristles
Feather Maintenence
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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 & 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 betakeratin
• 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
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
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See handout, look for examples in lab
Foot arrangement
Toes
Beak Shapes
Wing Shapes
etc. etc.