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 Western gull Immature Herring gull

Early juvenal to adult plumages (3-4 years) Slaty-backed Gull

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 post- breeding 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 Most birds molt sequentially, e.g. innermost primary outward Some species, e.g. many ducks, molt all flight feathers at once 1 st primary starting to grow all primaries done, secondaries growing Female American Goldfinches

‘A Bird of Prey’. Engraving from Punch 14th May 1892

Spectacular feathers Scissor-tailed flycatcher Quetzal Sulphur crested cockatoo hoopoe