 The flight feathers of adults and juveniles can differ considerably in length , particularly among the raptors . Overall , juveniles tend to have slightly longer rectrices , and shorter , broader wings ( with shorter outer primaries , and longer inner primaries and secondaries ) than do adults of the same species . However , there are many exceptions . In longer @-@ tailed species , such as swallow @-@ tailed kite , secretary bird and European honey buzzard , for example , juveniles have shorter rectrices than adults do . Juveniles of some Buteo buzzards have narrower wings than adults do , while those of large juvenile falcons are longer . It is theorized that the differences help young birds compensate for their inexperience , weaker flight muscles and poorer flying ability . 
