Feeding Nestling in Twite Acanthis flavirostris at the Haibei Alpine Meadow,Qinhai

Data on parental feeding rates of Twite Acanthis flavirostris were collected at Haibei Alpine Meadow Ecological System Station,the Chinese Academy of Sciences in 3 breeding seasons (May-August) in a period from 1999 to 2001.Using a closed-circuit television system,which included a camera nearby the nest and a monitor 35-40 m away from the nest,the feeding courses were seen.There were no differences in the feeding rates among the years,and also no difference between male and female parents.The total feeding rate of parents did not change with the age of nestlings,and with time of day,but the rate of males was higher than that of females before twilight,and reversed during twilight.The rate of males was higher than that of females before 6 days of nestlings age,and then the rates closed to the same level.Those sexual differences can be related to the differentiation of roles in rearing nestlings except the feeding:females were exclusively in charge of keeping warm for and sheltering nestlings from strong sunlight,and removing feces of nestlings from nests.Those results were in keeping with the theory of parental investment in monogamous avian.