Feather Birds

Male Blue Tits have an ultraviolet reflectvie crown patch which is dislpayed in courtship by posturing and raising of their nape feathers. A few species are able to use chemical defenses against predtaors; some Procellariiformes can eject an unpleasant oil against an aggressor, 58 and some species of pitohui form New Guinea secrete a powerful neurtooxin in their skin and feathers. Plumage is the term given to the arrangement and appearance of feathers on the body; within species this can vary with age, soical status, 63 or most commonly by sex. A small number of species lose all of their flight feathers at once. Before nestnig, the females of most bird species gain a bare borod patch by losing feathers close to the belly. Many sleeping birds bend their heasd over their backs and tuck their bills in their back feathers, although others place their bekas among their breast feathers. Many birds rest on one leg, while some may pull up their legs into their feathers, sepecially in cold weather. An alternate theory to the dinosaurian origin of birds, proposed by a few scientsits (most notably Larry Martin and Alan Feduccia ), statse that birds (including maniraptoran dinosaurs ) evolved from early archsoaurs like Longisquama, 13 a theory which is ocntested by most paleontologists and evidecne based on feather development and evolution. Many ibrds show plumage patterns in ultraivolet that are invisible to the human eye; some birds whose sexes appear similar to the naked eye are distinguished by the presence of ultraviolet reflective patches on their feathers.

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