The relation between climate and species abundance has long been recognized (Andrewartha and Birch 1954), and current research uses this relation to inform study of species’ responses to climate change. Bird species are much loved and much studied, with distribution and abundance profiles that are perhaps best known among the vertebrates. Avian species’ responses to climate change are being studied in both terrestrial and marine environments, with large effects of changing climate already documented for birds in each realm. Examples of climate effects on seabirds show that rising sea surface temperature has been correlated with a 90% decline of sooty shearwaters; a change in the underlying food web was implicated (Veit et al. 1997). Change in underlying food web was also implicated in a correlation between changing sea surface temperature and abundances of two murre species (Irons et al. 2008), though a study of the effects of climate on fulmar population sizes shows that climate change effects can take time to manifest (Thompson and Ollason 2001). Research on climate effects on terrestrial birds are mainly focused on distribution changes (Huntley et al. 2008), though there is a growing literature on changes in migration phenology (Cotton 2003, Crick 2004, Buskirk et al. 2009), and some research on changes in food source levels (e.g., Baker et al. 2004). We seek to synthesize variation in climate and its impacts on both land and sea birds according to time scale over which that variation occurs. Time series analysis of climate variability shows distinct peaks at seasonal, annual and decadal scales. Birds respond at each of these scales, but the response by terrestrial birds is at different temporal scales than that of seabirds. These differences reflect both the life histories of the birds and the patterns of variability in their respective environments; response times for terrestrial birds are likely driven by physiological responses, while response times for seabirds are likely driven by climate impacts on food sources.