| Reasearch in avian life-history has a relatively long period. Birds played a critical role in the development of life-history theory. In this thesis, we present a research on the life-history traits on black redstart during the breeding season from 2008 to 2009 in Gahai-zecha Nature Reserve.Sexual dimorphism in plumage is significant in black redstart. The body weights of male are relatively steady (18.71±0.56 g) during the whole breeding season, while the weights of female differ significantly from early breeding season to late breeding season (early 20.65±1.53 g, late 18.04±1.27 g). Black redstarts in the study area usually nest in cavities. Weights of different nests are significant difference, from the lightest one is 14.74 g to the heaviest one weight is 74.52 g, which is related to the nest site reusing (reusing rate:30.77%). Egg colour of black redstarts is light green. Mean egg volume is 2.31±0.19 cm3, mean egg weight is 2.51±0.21 g, relatively egg weight is 12.54%, and mean clutch size is 5.08. There is a strong positive relationship between egg size and laying order (r=0.397, p=0.030), which shows that this species adopts'brood survival strategy'. Egg size has a strong negative relationship with clutch size (r=-0.274, P=0.002) that present a trade-off between these two life-history traits. Egg volumes were significantly different (t=4.081, df=122, P<0.001) in two breeding seasons, whereas clutch size shows no significate change (t=-1.304, df=23, P=0.205). Only female incubate the eggs, mean incubationg rate is 68.67% and incubation period is 13.41 days. Both parents feed the nestlings, nestling period is 17.53 days and feeding rate is 4.46±0.27 times/nestling/h.66.67% females have two breeding attempts, but egg size, clutch size, hatching rate and fledging rate of the two attempts have no significant differences. Nest success rate, hatching rate, fledging rate and reproduction success rate in the two breeding seasons count up to 70.83%,69.42%,78.57% and 54.55%. Black redstarts prefer nest site in clay cavities and the orientation of nest entrances usually expose towards southeast and southwest. Similar to predation risk, human disturbances can have effects on nest site selection of bird. The black redstarts were found to shift their nests to relatively deeper location in the cavity in the subsequent breeding season after human disturbance. The results in this study suggest that the black redstarts exhibit adaptive behavioral plasticity associated with concealment.High-elevation is expected to have affections on life-history evolution in bird. By comparing egg size, clutch size and fledging rate of different species in the genus of redstart, it is found that high-elevation species had significantly smaller clutch size but bigger egg size. However, these two life-history traits have no correlation with elevational gradient in intraspecies of black redstart. This may be caused by evolutional time length, which still need more research to testify.
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