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 • Coloration to flight – Pigments – Structural Colors
• Structure & Variation • 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 BOARD – Barbs, barbules ILLUSTRATION • Proximal and distal – Superior & inferior umbilicus – Pennaceous & plumaceous barbs – Pulp caps
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 BOARD ILLUSTRATION • Rectrices – Tail feathers provide lift, rudder and breaking capabilities for birds Cedar Waxwing
Rectrices
1º 2º 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
Head
Wings Anchiornis Feather Coloration Feathers of Dinosaurs & Birds
Ancient & Modern Fossil Birds Sinosauropteryx
P owered Flight
First Appearance of Color Patterns In Gliding Dinosaurs First Appearance of Color Patterns in non-Volant Dinosaurs Protective Care for Feather Investment
• Preening • Anting--formic acid protection – Removes ectoparasites • Sunbathing – Streamlines feathers – Heating in TVs • Oil secretions – Drying in Anhinghas – Uropygial gland – Keep feathers supple – Anti-parasite chemical • Dust & Water Baths 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.