Abstract: In North America, over 200 bird species use mountain habitats for a portion of their life cycle. Birds have developed a range of adaptations that facilitate persistence in the structurally simple but stochastic mountain environments. Alpine songbirds have larger mass to ameliorate thermal regimes, morphological adaptations to improve flight stability in wind, and can adjust stress hormone levels to allow breeding in conditions that result in abandonment of reproduction in low elevation birds. Alpine ptarmigan cope with high breeding failure with extensive renesting, population rescue by external recruitment, and increased longevity compared to low elevation arctic ptarmigan. An unrecognized feature of alpine biodiversity is the extensive autumn migration stopovers or upslope movements from forests to mountain habitats. In coastal and interior British Columbia, ~ 114 species of songbirds, raptors, waterbirds and others use montane, sub-alpine and alpine habitats from July through October. Sub-alpine shrub and wet meadows are important migration habitats, as well as alpine grasslands and montane conifer forests. Avian research in mountain habitats highlights the importance of connectivity processes such as dispersal rescue for population persistence, and inter-seasonal connectivity during migration for vertebrates from high latitudes and lower elevation forests. Climate variability impacts, atmospheric deposition and anthropogenic influences from low elevations are critical stressors expected to influence the abilities of mountain birds to ‘stay on top’.

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