a feather from the whippoorwillfacultyweb.cortland.edu/broyles/411/feathers.pdfflight feathers •...
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A Feather from the Whippoorwill (Emily Dickinson, 1955)
A feather from the Whippoorwill
That everlasting -- sings!
Whose galleries -- are Sunrise –
Whose Opera -- the Springs –
Whose Emerald Nest the Ages spin
Of mellow -- murmuring thread –
Whose Beryl Egg, what Schoolboys hunt
In "Recess" -- Overhead!
Photograph by Robert Clark—Audubon Magazine 2012
Avian Feathers
Function, Structure & Coloration
• Tremendous Investment
– 25,000 on Tundra Swan
– 2-4,000 on songbirds
– 970 on hummingbird
• Feather Mass=2-3X Skeletal Mass
• 91% Protein (keratin)
1% Fat, 8% water
• Waxy secretions and fatty acids from uropygial gland protect feathers
Feather Outline
• Functions in addition
to flight
• Structure & Variation
• Coloration
– Pigments
– Structural Colors
• Origin of feather color
and recent fossil
discoveries
Do feathers have a function or are
they just an expensive costume?
• Insulation
• Sound production
• Sound capture
• Camouflage
• Aerodynamics
• Sexual selection
• Protection
• Nesting, diet, other
Diverse Functions
• Crypticity
– Disruptive color patterns in
Killdeer and meadowlarks
– Mimicry in bitterns, snipe, and
woodcock
Diverse Functions
• Sound production for attraction – Booming of Ruffed Grouse wings
– Primary flight feathers of American
Woodcock
– Hummingbirds
• You Tube Hummingbird Music
– Manakins
• Manakin Wing Sound
Diverse Functions
• Sound gathering properties
of owls and some hawks
– Eastern Screech Owl
– Northern Harrier (hawk)
http://www.wisenaturephotos.com/NEW!!!%202-10-06.htm
Diverse Functions
• Support
– Tail rectrices of woodpeckers
• Protection
– Bristles over nares
Diverse Functions
• Display
– Aggression
• Red-winged blackbird threats
• Sun Bittern
– Attraction --sexual selection
• Peacock tails, colorful plumages
• Tail length in Barn Swallows
Diverse Functions
• Thermoregulation
– Heat retention, natal down
– Convective heat loss--radiation cooling
– Solar heating
White in Winter
• Air spaces in feathers scatter light
• Dual Functions – Insulation
• white plumage and pellage has a higher insulation value
– Crypticity
• avoid predation or be a more effective predator
Feather Structure
• Epidermal and epithelial
development
• Terms
– Rachis
– Barbs, barbules
• Proximal and distal
– Superior & inferior
umbilicus
– Pennaceous & plumaceous
barbs
– Pulp caps
BOARD
ILLUSTRATION
Down Feathers & Contour Feathers
• Plumaceous vanes close to
skin provide excellent
insulation
• Heavy down coat in
waterfowl • Cover feathers
• Smooth the non-
aerodynamic edges and
folds of the avian body
• Substantial pennaceous
and plumaceous barbs
Bristles & Filoplumes
• Thin, hair-like, facial feathers
– Protection of eyes--woodpeckers
– Tactile, insect collection--nightjars
Filoplumes
• Whisker-like feathers
hidden throughout
plumage
– Believe to enhance tactile
and sensory capabilities
http://www.reinhold-necker.de/seite4.html
Flight Feathers
• Remiges
– Primaries attached to manus
– Secondaries attached to ulna
– Provide airfoil surface for flight
• Rectrices
– Tail feathers provide lift, rudder
and breaking capabilities for
birds
BOARD
ILLUSTRATION
Cedar Waxwing
1º 2º
Rectrices
Flight Feathers
• Remiges
– Primaries attached to manus
– Secondaries attached to ulna
– Provide airfoil surface for flight
Flight Feathers
• Rectrices
– Tail feathers provide lift, rudder
and breaking capabilities for birds
Feather Coloration
• Melanins--oxidized products of
tyrosine
– Dark colors--black, gray, dark brown, brick
red
• Temperature regulation
• Longevity of feathers
• Gloger’s Rule--darker colors in
humid tropical regions
• Melanosome shape and density
determine whether feather is gray,
black, or rusty
What do the following birds
have in common?
Snow Bunting Whooping Crane
What do the following birds
have in common?
Snow Goose Northern Gannet
What do the following birds
have in common?
Gull Red-footed Booby
What do the following birds
have in common?
Scarlet Tanager American Goldfinch
Feather Coloration
• Carotenoids--diet derived pigments of a plant source
– Brilliant yellows, oranges, and reds
– Rarely found in wings
• Carotenoid Stories
– Cedar Waxwings
– Flamingos
– House Finch
Recent color variation in rectrices of Cedar Waxwing.
Orange or Yellow?
Where does the Egyptian Vulture
obtain its Carotenoids?
Moniguero--dung eater in Spanish--Coprophagy
Psittacorfulvins “the other red pigment”
• Found in all members of the Psittaciformes
• Endogenous production
• Resistant to Bacillus licheniformis
Structural Colors • White, blue, and some green colors are
formed by air spaces around deep
embedded melanosomes
– Short wavelength light is easily reflected in air
• Blue Jay, Indigo Bunting, Honeycreepers
Structural Colors
Iridescence
• Structural color where the viewpoint of the observer determines and direction of light source vary
• Interaction of surface layers, melanin granules, and air spaces of barbules
• Hummingbirds & grackles
Origin of Feathers & Coloration
• Anchiornis huxleyi
– meaning “near bird”
– 150-161 MYA
– Considered a dinosaur with
wings and feathers
– Glider
• SEM analysis of feather
impressions
Li et al., 2010. Plumage color patterns of an extinct dinosaur. Science 327:1369.
Anchiornis Feather Coloration
Melanosome Fossil Impressions
Wings
Head
Anchiornis Feather Coloration
Feathers of Dinosaurs & Birds
P owered Flight
First Appearance of Color Patterns
In Gliding Dinosaurs
Ancient & Modern Fossil Birds
First Appearance of Color Patterns
in non-Volant Dinosaurs
Sinosauropteryx
Protective Care for Feather Investment
• Preening
– Removes ectoparasites
– Streamlines feathers
• Oil secretions
– Uropygial gland
– Keep feathers supple
– Anti-parasite chemical
• Dust & Water Baths
• Anting--formic acid protection
• Sunbathing
– Heating in TVs
– Drying in Anhinghas
Feather Detectives
• Why would professionals from the
following disciplines / organizations want
feathers identified?
– Federal Aviation Administration
– FBI and USFWS
– Archeologists
– Ecologists
Plumage / Molts
• Basic--non-breeding plumage, female-like
• Alternate--breeding plumage
• Timing--post-breeding, pre-migratory – Usually annually, sometimes 2X
• Feathers are molted in sequence – Inner primaries to outer primaries
• Why molt?
www.jkcassady.com/images/1SCTA0902.jpg
Molting and Life History of
American Redstart
• Hydrogen Isotope data
– Indicates location of
bird during molt
• Males that molt on the
run have lower
carotenoid content in
feathers
Norris, et al. 2004. Reproductive effort, molting latitude, and reproductive effort in a
migratory songbird. Science 306:2249
Molting and Life History of
American Redstart
• Males that fledge young,
molt further south
• Males that fledge young
later in the season molt
further south
• Males with greater
reproductive effort molt
further south
Balancing Reproductive Effort and
Survival in American Redstarts
• Males that delay migration,
molt during stress, arrive later
to winter grounds, and may
lower reproduction the
following year
• Males with low reproductive
effort, molt during period of
low stress, arrive earlier to
wintering grounds, and may
improve reproduction the
following year.