Effects Of Body Condition On The Reproductive Investment Of Yellow-Rumped Flycatcher (Ficedula Zanthopygia)

Morphological characteristic is the most obvious aspect of phenotype in birds, as the characteristic could be affected by natural selection and sexual selection and supposed to deliver the information of individual quality. In birds, individuals have different body condition which may affect the reproductive investment. We conducted a study on the effects of body condition on reproductive investment in the Yellow-rumped Flycatchers(Ficedula zanthopygia) inside artificial nest box in secondary-forest of Zuojia nature protection area in Jilin Province from March to July in 2014-2015.During the study period, we found 58 nests of Yellow-rumped Flycatcher. The mean weight of nest materials was 36.61±11.36 g. The average clutch size was 6.16 ± 0.71 and the average reproductive success was 82.76%. The hatching and the fly rate was the highest when the clutch size was 6. In this study, the date of first egg laid was 10 th May and the last date of laying egg was 7th June. The average time of laying first egg was 21 th May. The peak time of laying eggs was at the end of May. There was significant negative correlation between clutch size and date of first egg(r =-0.519, P < 0.001).The results showed that the difference of bill length, wing length, tail length, tarsus length, body weight and body condition which were from individual was significant, indicating that the individual quality was possibly different. The results revealed that female body condition had no significant correlation with the laying time, clutch size, nest material weight and carried nest material times. Male body condition had negative correlation with the laying time(r =-0.525, P < 0.001), and positive correlation with clutch size(r = 0.312, P = 0.029). The remarkable correlation between female body condition and incubating duration was found(r = 0.367, P = 0.013). By observing and analyzing the all-day videos of parental behavior in incubation period, this research found incubation behavior was the main behavior in the incubation period, which accounted for 68.75% of the time. And the mean incubating duration of day was 330 min. The results showed that there was no significant difference in the daily rhythm of incubating duration(F = 0.58, df = 7, P = 0.773 > 0.05). There was no obvious hatching peak, which suggested the female in incubating duration all day. We also found that adult body condition had no significant correlation with brooding times. In addition, brood size was positively correlated with brooding times(r = 0.552, P < 0.001). The results showed that there was no significant difference in daily rhythm of female(F = 0.399, df = 7, P = 0.901 > 0.05) and male brooding(F = 1.747, df = 7, P = 0.105 > 0.05). There was a significant difference in biparental mean feeding times(t = 2.989, P = 0.004 < 0.05). The feeding rate of females was higher than that of males at the 7 days of nestlings. This paper indicates that Yellow-rumped Flycatchers can regulate their reproductive investment according to their own or mate’s body condition.