Study On The Influence Of The Nest Construction Cost And Nest Structure And Their Effect On Breeding In Varied Tit(Parus Varius)

Birds' nests are special structures built with reproductive aims.Nesting period is an important part in the process of breeding.This study examined the factors that influence the nest construction cost(the total weight of the nest)and nest structure(nest size,weight of each nest material and their proportion)and their impact on breeding performance of Varied Tit(Parus varius).This research is divided into four aspects: Firstly,the influence of climate factors on the nest construction cost and nest structure;Secondly,the influence of extra-pair paternity on the nest construction cost and nest structure;Thirdly,the relationship between the nest construction cost and nest structure and physical quality of parents and offspring;Fourthly,the influence of the nest construction cost and nest structure on reproduction.The results of the study are as follows:(1)In 2016,we obtained 40 nests of Varied Tit to examine the influence of climate factors on the nest construction cost and nest structure.The results showed that the temperature factor was negatively correlated with the mass of fur and its proportional contribution to the total nest mass.Other factors were not significant.The results showed that birds could adjust the thermal insulation properties of their nests to adapt to climate change.(2)We collected 21 nests with extra-pair offspring and 13 nests without extra-pair offspring,total 34 nests.The results showed that there were no significant differences between EPP nests and none-EPP nests about the nest construction cost and nest structure.The results showed that EPP had no influences on nesting behavior.(3)We collected 36 female,28 male and 159 offspring physical quality data of Varied Tit,the analysis results showed that the mass of male and female were positively correlated with the mass of moss and its proportional contribution to the total nest mass.Female body mass and the length of tarsus were positively correlated with the volume of nest cup.These mean that the heavier the parents' weight,themore the moss in the nest;the heavier the female's weight and the longer the tarsus was,the larger the nest cup volume was.The results reveal that the parental“quality” has a direct effect on nest “quality”.In addition,the total mass of nest was positively correlated with the body mass and length of tarsus of the offspring;the mass of moss and its proportional contribution to the total nest mass were positively correlated with the length of tarsus of the offspring.These means that moss is a kind of important nest materials in Varied Tit nests.It could not only reflect the quality of parental,but also has important positive influence on the growth of offspring.Meanwhile,the nest construction cost is good for the offspring.(4)Our results showed no correlation between the total mass of nest and the breeding parameters of Varied Tit.Nest cup volume was negatively correlated with the date of first egg;the mass of moss and its proportional contribution to the total nest mass were positively correlated with the breeding success rate.Nest cup volume directly reflect the body size of incubation parent,so the larger the parent birds,the earlier their breeding start.Based on the results,we could draw a conclusion that factors affect the nest construction cost and nest structure of Varied Tit mainly included: temperature factors,the mass of breeding parents and the length of tarsus of female;EPP had no effect.The influence of nest construction cost and nest structure on breeding mainly reflected in the impact on offspring growth and reproductive success.