Transcript Feathers III: Molt, plumages

Plumage Studies
• Roxie Laybourn,
Smithsonian Institution
• Feather identification
expert
– Smuggling
– Aviation accidents
– Rare bird identification
• Museum of Natural
History at Smithsonian
Inst. has over 650,000
specimens
Plumage I: Growth
• Birds have a series of plumages
• Growth & maturation
– Natal down to adult plumage
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Psilopaedic typical on altricial birds
Ptilopaedic on precocial birds
First fragile feathers only 1-2 weeks
May have second set of down, most have juvenal plumage,
including wing and tail feathers
• Parts of juvenal plumage replaced with either immature or
adult plumage
Juvenal & Adult Robins
Gulls
• Rule One still applies: some gulls are unidentifiable
– From review of the book: Gulls of North America, Europe, and Asia
Immature Herring gull
Immature Western gull
Slaty-backed Gull
• Early juvenal to
adult plumages
(3-4 years)
Plumage II: Seasonal
• Two primary purposes
– Migration preparation
– Mating and breeding preparation
• Most adults molt after breeding
– May keep plumage entire year
• Can still change appearance as feather tips wear off - meadowlark
– May partially replace before breeding next year
Yellow rumped warbler
• From left top
– Juvenal
– Winter
– Spring
– Summer breeding
Molt
• Plumage at first molt postbreeding is “basic”
• Breeding plumages are
“alternate”
Female
Male molting
Male breeding
plumage
Molt purposes
• Replace wornout feathers
• Be cryptic in non-breeding season, more sexually
attractive in breeding season – ecological tradeoff
off of reproduction pressure vs. predation pressure
• Eclipse or cryptic plumage for many females especially at nest; juveniles, non-breeding males
• Infestation of parasites can destroy plumage rapidly
• Some species do several partial molts annually
Molt Patterns
all primaries done,
secondaries growing
1st primary starting to grow
• Most birds molt
sequentially, e.g.
innermost primary
outward
• Some species, e.g.
many ducks, molt all
flight feathers at once
Female American Goldfinches
www.westol.com/~banding/Pictorial_Highlights
‘A Bird of Prey’.
Engraving from Punch 14th May 1892
Spectacular feathers
Sulphur crested cockatoo
hoopoe
Scissor-tailed flycatcher
Quetzal