Raising chicks - Ikusou

The act of parent birds raising their young. Like mammals, birds have a well-developed habit of not abandoning their young after they are born, but rather raising them for a certain period of time. Raising the young includes keeping the chicks warm, feeding them, avoiding predators, and defecation. In pheasants and ducks, which have precocial chicks that can walk shortly after hatching, the parent birds quickly leave the nest with their chicks and take care of them while they move around together. In small birds such as sparrows, swallows, and great tits, which have altricial chicks that can hardly do anything on their own, the parent birds bring food to the chicks in the nest. They also eat the feces made by the chicks in the nest, or take them away from the nest to discard them. Parent birds of this type continue to look after their chicks for a while after they leave the nest. In general, brooding is done by both sexes in birds that breed in pairs, and by females alone in birds that breed polygamously or promiscuously, such as birds of paradise and ptarmigan. When used as a livestock term, it refers to raising chicken or turkey chicks using electric heaters.

[Higuchi Hiroyoshi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

鳥類の親が、子である雛(ひな)を育てること。鳥類では哺乳(ほにゅう)類と同じく、生まれた子を放置せず、一定期間育てる習性がよく発達している。育雛のなかには、雛の保温、給餌(きゅうじ)、外敵の回避、排糞(はいふん)などが含まれる。孵化(ふか)後まもなく歩き出せる早成性の雛がいるキジ類やガンカモ類では、親鳥は雛を連れて、はやばやと巣を離れ、雛と行動をともにしながら世話をしていく。スズメ、ツバメ、シジュウカラなどの小鳥類のように、自分ではほとんどなにもできない晩成性の雛がいる鳥では、親鳥は巣内にいる雛に食物を運んでやる。また、巣内で雛がした糞は食べてしまうか、巣から離れた所まで捨てにいく。このタイプの親鳥は、巣立ち後もしばらくは雛の世話をする。育雛は一般に、雌雄1羽ずつのつがいで繁殖する鳥では雌雄両方が、フウチョウ類やライチョウのように一夫多妻や乱婚形式で繁殖する鳥では雌だけが行う。なお畜産用語として用いられる場合は、ニワトリやシチメンチョウの雛を、電熱器などを使って育てることをさす。

［樋口広芳］

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