Study On Reproductive Investment And Influencing Factors Of Sitta Europaea Incubation Period

The reproductive behavior of the animals is related to the survival of the whole population.The reproductive investment and successis a hot topic for concerned in bird ecology research.Hatching is an important part of the breeding process of birds,the incubation time was varied with a a lot of factors,such as clutch size,physical condition of females and breeding time.From March to July in 2014 and 2015 at Zuojia Nature Reserve of Jilin Province,we used artificial nest box to attract the Sitta europaea and observed the reproductive input of them..We explored the effects of clutch size,the first egg laying date and the physical condition of parents on the reproductive investment during the incubation period.During the study period,the nesting rate was 48.65%and the average clutch size was 6.65 ± 1.31.In this study,the first egg production date is lasted from April 20to May 17.The average first egg production date was April 30,and the egg-laying date was mainly concentrated in late April.There was a significant negative correlation between cutch size and the first egg production date(r=-0.451,P<0.046).Incubation is the main behavior of female,the average daily incubation time is 471 min,accounting for 65.41%of the total time,followed by time for leaving nest which accounted for 26.86%and the time used for alert which accounted for 7.32%and the time used for turning the egg which accounted for 0.41%.The earliest incubation date is April 27,the latest incubation began in May 23.The average hatching period was 15.7 ± 1.2 days(n= 20),and the difference of incubation period among nests was not significant(P= 0.145).The hatching period varied from 14 to 18 days.There was a positive correlation between clutch size and the average incubation period(r?0.273,P= 0.244,n = 20).There was a significant negative correlation between the first egg laying date and the duration of the incubation period(r=-0.465,n= 20,P= 0.039).The one way ANOVA results showed there was a significant differences of female sitting time between the early stage and the middle stage of incubation period(P<0.001,n = 20),there was a significant differences of female sitting time between the early stage and the late stage of incubation period(P<0.001,n =20),There was no significant difference between the middle and the late stage(P =0.324,n =20).There was a significant positive correlation between the time for sitting in nest and clutch size(r= 0.705,P<0.001).The results showed that there were differences in body length,beak length,wing length,tarsus plant length,body weight and body condition among individuals,indicating that there may be physical condition differences among individuals(r =-0.472,P<0.035),and there was a significant positive correlation between clutch size and female physical condition(r= 0.622,P= 0.003).There was a significant positive correlation between the condition and hatching time(r= 0.444,P= 0.050).The results of the study indicated that Sitta europaea can adjust the reproductive investment based on their own physical conditions and clutch size.