birdsarewarmbodiedcreatureswithwingsandfeathers.thebodytemperatureofbirdsisgenerallyhigherthanthatofhumans,sotheyseemwarmtothetouch.birdslayeggswhichtheyincubateuntilhatching--or,insomecases,getsomeotherbirdtodotheincubating.insomespeciessuchasoursongbirds,theyounghatchnakedandhelplessandmustbefedandcaredforbyaparentbird.others,likethechickensandtheirrelatives,producedown-coveredyoungthatareablerunaboutandfeedthemselves.theyarestilldependentforprotectionuponadultbirds.鸟有温暖的翅膀和羽毛。鸟类的体温一般高于人类,所以他们似乎是温暖的触摸。鸟产卵孵化,他们直到孵化-或者,在某些情况下,得到一些其他的鸟来孵化。在一些物种,如鸣鸟,年轻的孵化赤裸无助和必须被喂养和照顾父母的鸟。其他人,像鸡和他们的亲戚,产生的有盖的年轻,是能够运行和养活自己。他们仍然依赖于成年鸟类的保护。