Birds {bird} have wings and feathers.
feathers
Feathers are modified reptile scales, decrease water and heat loss, and aid flying. Light scattering causes blue jays to have blue feathers. Transparency causes white feathers [Matthews, 1973]. Females typically are drab, and males have color.
flying
Bigger birds fly faster. Penguins cannot fly but use wings for swimming by flying under water.
bone
Birds have hollow bones.
metabolism
Birds live several years. They have fast heartbeat, high blood sugar, and high blood pressure. They have fast transit time for digestion. Birds are warm-blooded.
respiration
Birds have lungs that exhale actively and inhale passively, by continuous airflow, because lung air sacs fill spaces between organs and in wings.
reproduction
Birds have fertilization inside female. Birds have eggs with hard shells.
signals
Birds have 10 to 40 different signals [Matthews, 1973]. Bird songs {birdsong} can be instinctual, learned, or irregular and are for warning, mating, or territory.
nervous system
Birds have optic tectum.
development
Both parents care for eggs and chicks.
evolution
Birds evolved from thecodont pterosaurs.
types
Protoavis [-220000000] had good eyes and bad olfaction and hunted by day. Special shoulder joints allowed later flying, as in Archaeopteryx [-150000000] and Confuciusornis sanctus [-120000000].
Biological Sciences>Zoology>Kinds>Bird
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Date Modified: 2022.0224