Parental Investment During The Incubation Period Of First Brood In The Great Tit(Parus Major)

Reproductive investment is a key life-history trait of birds,which directly affects the reproductive success of birds.The incubation period is one of the important processes in avian breeding cycle,parents need to make a trade-off between parental care and self-existence.Although it has been researched in numerous studies on reproductive investment of avian incubation,few studies researched the combined effects of intrinsic and extrinsic factors on parental investment during incubation period.From March to July of 2015 and 2016,I researched parental investment of incubation period of first brood in the Great Tit(Parus major)which bred in artificial nest-boxes at Zuojia Nature Reserve of Jilin Province.A half-day video were used to record female nest attentiveness and rates of females feeded by males.Nest intruder experiments were simulated by using fingers to test the female defence intensity.Alarm calls playback experiments were used to test the defence intensity of males.Simultaneously,we investigated the effects of intrinsic factor and external factor on parental investment during incubation period,such as laying date,clutch size,body condition of parents,ambient temperature.Results showed that female nest attentiveness was positively related to clutch size,incubation days,laying date.While,the female nest attentiveness was negatively related to ambient temperature.Male incubation feeding was positively related to clutch size.Male incubation feeding was negatively associated with ambient temperature.Male nest defence intensity was positively related to male body condition.Female nest defence intensity was positively related to clutch size.Hatching success was positively related to clutch size.Results of this study indicated that Parus major could regulate their reproductive investments of incubation period according to clutch size,laying date,body condition and ambient temperature.