| During feeding period,offsprings of altricial birds are usually cared by biparents.In order to survive better,they compete for more food or better living environment.Meanwhile,parents distribute food to offsprings depending on the signal of their begging,their sex,and whether is extra-pair offsprings.We investigated the behavior of parental care in 22 broods of Parus varius by video recording from March to July in 2011 and 2012.Of the 22 nest recorded,only 16 had been avaliable.We analysed the behavioral parameters,including parent locations,nestling positions,begging intensity of the nestlings,and parental feeding.We also used sex-identify and paternity identification to analyse the sex and extra-pair offsprings(EPO)of all nestlings.There are 11 nests with extra-pair copulations(EPY)phenomenon.We investigated the behavior of parent-offspring communication through 7 broods of the Parus varius by the whole day video recording in 2011.Results showed that:(1)male and female parents had different locations.During the whole feeding period,brood males preferred standing closer to the nest entrance.In contrast,positions of females were more flexible,in that they stood relatively far away from the nest entrance in the early stage and relatively close to the nest entrance in the mid and late stage of feeding period;(2)nestlings that begged for feed more intensely and those occupied positions closer to the provisioning parent had a higher probability of receiving food from both parents;nestlings that farther away from parents had a lower begging intensity.Thus,positions had the strongest influence on the food receiving of nestlings;(3)females played an important role in the feeding period,whose feeding frequency was significantly higher than the males P<0.01;(4)nestllings' begging intensity and parental feeding frequency varied greatly at different stages of the feeding period,while the later period had the lowest intensity;(5)females showed no preference on the size of nestlings P>0.05,whereas males preferentially provided food for the largest-sized nestlings in the whole brood P<0.01.These results suggest that the food-distribution pattern in Parus varius is determined by nestling behavior and body size,and nestlings will also adjust their postions and feeding behaviour according to their age.Combined with the 2011 and 2012 video data and experiment result,explore whether parental could recognition EPO during the breeding.The following analysis is based on 11 nests with EPO except others had been described.Results showed that:(1)in feeding period,obtainning food of any young birds was balanced.The nestling wether is legitimate didn't affect parental feeding preference,but nestllings' begging intensity and positions were the main cue which adults adopted to making their feeding decision during each feeding event(P<0.01,n=11);(2)female showed no preference on the sex of nestlings P>0.05,whereas males preferentially provided food for the female nestlings P<0.01;(3)the extra-pair offsprings begging intensity was greater than within-pair offsprings(WPO),but the position was much further(P<0.05);(4)the nestling of different gender had no significant of begging intensity and positions(P>0.05);(5)the food allocation of parental wasn't related to the young bird tarsus length,brood size,time of year,color of chick head(n=16);(6)Whether having extra paternity offspring' nest,the brood number was no significant difference.And the female of containing extrapair young(EPY)nest feeding frequency was significantly higher than no EPY(P<0.01,n=12),the males showed no preference on whether there were EPY.These results suggest that Parus varius parental could not identify EPO,but the male parent prefer to feed female nestling. |
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