Migration distance is a fundamental axis of the slow-fast continuum of life history in boreal birds

Abstract Seasonal migration is intrinsically connected to the balance of survival and reproduction, but whether migratory behavior influences species’ position on slow-fast continuum life history poorly understood. We found that boreal-breeding birds migrate long distances exhibit higher annual adult lower reproductive investment relative co-distributed boreal species shorter winter closer their breeding grounds. Our study uses “vital rates” data output survivorship compiled from literature for a assemblage 45 mostly passerine birds. These breed sympatrically in North American forests diversity environments northern winter. After controlling body size phylogeny, distance apparent are positively related across species. Both correlated with wintering warmer, wetter, greener. At same time, longer migrations associated reduced time spent grounds, clutch sizes, fecundity (clutch × maximum number broods per year). Although seasonal often high mortality, our results suggest long-distance imposes selection pressures both confer demand rates. That is, owing cost migration, this strategy can only persist if balanced by survival. supports idea evolves promote environments. In birds, evolution longest yields highest survival, at an inherent fecundity. therefore reveal as fundamental axis predicts, inextricable from, reproduction.