Climate change research has been largely focused on projecting changes in species' distributions, which have included projections of dramatic shifts and contractions in species' ranges. These projections suggest that many local populations will decline as species' range limits retreat, but they reveal little about the processes that may produce these declines and range shifts. A better understanding of these processes, and of the effects of climate change on local populations, may be obtained by projecting the changes in local demographic rates in response to climate change. I collaborated with biologists from PRBO Conservation Science to examine in detail the effects of weather and project the impacts of climate change on adult and juvenile survival rates in a Song Sparrow (Melospiza melodia) population at the Palomarin Field Station in central coastal California. In chapter 1, my co-authors and I examined multiple hypotheses for the direct and indirect effects of weather on adult and juvenile survival rates using a mark-recapture data set spanning 1979-2010. We found that a direct effect of winter weather had a strong effect on adult survival, while an indirect effect of prior winter weather had a strong effect on juvenile survival. As a result, in response to climate change, we projected a significant increase in mean adult survival and a smaller decline in mean juvenile survival. Our results underscore the importance of considering both direct and indirect effects of climate change, as well as the potential for mismatches in the responses of different life stages to changes in environmental conditions. This theme of mismatches in the responses of different life stages to environmental conditions was echoed in chapter 2, in which my co-authors and I examined differences in the survival of dependent and independent juveniles. We found that prior winter precipitation had a strong positive effect on the survival of independent juveniles, consistent with an influence on food availability and the results of chapter 1, but had little effect on the survival of dependent fledglings, who benefited from the foraging skills of their parents. The effect of prior winter precipitation on independent juveniles also contributed more to the total variation in juvenile survival than any other variable we considered. We concluded that the survival of independent juveniles is a major driver of annual variation in juvenile survival, and that identifying the effects of weather on the survival of independent juveniles will be essential to understanding and projecting responses to climate change. Although the survival of dependent fledglings is less sensitive to environmental conditions than independent fledglings, survival was lowest during this stage, forming a critical bottleneck in the population dynamics. In chapter 3, I examined individual factors influencing survival during the dependent, post-fledging stage. I conducted a 3-year radio-telemetry study on the post-fledging survival of juvenile Song Sparrows, and used this data to examine two hypotheses for the mechanism behind the often-reported relationship between nestling body condition and post-fledging survival: (1) the frequently-proposed body fat hypothesis, in which nestlings that are relatively heavy for their size have more body fat and are more able to cope with temporary food shortages; and (2) the mobility hypothesis, in which relatively heavy nestlings have heavier, more developed muscles and are more mobile at fledging, making them better able to escape predation. I found little support for the body fat hypothesis, and strong support for the effect of fledgling mobility on post-fledging survival. However, nestling body condition was not related to fledgling mobility. I concluded that because body condition scores may integrate the varying effects of multiple underlying factors, identifying effect of body condition on post-fledging survival may not be as informative as directly assessing the effects of functional traits, such as mobility, and that variation in fledgling development has a strong influence on post-fledging survival. This detailed investigation of the sources of variation in survival provided insights into the ecological differences between adults and juveniles, and between dependent and independent juveniles. Understanding which life stages are most affected by which individual and environmental factors is essential to developing effective conservation plans, including climate change adaptation plans. For example, although this Song Sparrow population overall may respond positively to climate change, this approach will be useful in other populations for identifying the demographic process(es) that will be adversely affected by climate change, and the mechanisms that may be responsible, such as the effect of drier conditions on food availability and the subsequent survival of independent juveniles. This information can in turn help prioritize future research and indicate management actions that may be effective in slowing or mitigating the effects of climate change for a population of concern.