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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 • • • • 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