Abstract: The study was conducted at Haibei Research Station of Alpine Meadow Ecosystem,Academia Sinica,during breeding seasons of 1987-1989.The development of thermoregulation during the nestling period in three species were examined.The three species have different type-nest.They are Houned Lark (Eremophila alpestris) nesting on ground and open,Twite (Acanthis flavirostris) nesting in shrub and open,and Hums Ground Jay (Pseudopodoces humilis) nesting in burrow and close.There were two developmental;modes in the process of a striking transition from an essentially poiklothermic condition to a state of homeothermy during the nestling period in three nestling species.The Twite was sharp mode,whereas the Hounded Lark and Hums Ground Jay were gradual mode.There was a optimun growth temperature in Houned Larkes at 35℃ that at which temperature the metabolism rates of nestlings during the developmental period did not vary with age increasing.