Although the extent to which large-scale environmental change will affect birds that breed in arctic areas will vary among species, reduced reproductive success and population declines have been observed in long-distance migrants and species whose reproduction depends on non-climatic cues. However, the proximate cues that birds use to determine timing of breeding and have not been examined across a broad taxonomic scale and remain poorly quantified for many species. Similarly, factors influencing the distribution and survival of nests are limited for many species, particularly those that breed in northern locations. This program evaluates the processes that influence timing of breeding, nesting distribution, and nest success across a range of taxa, thus improving predictions of how avian populations will respond to changing environmental conditions across their ranges.