Survival is negatively related to basal metabolic rate in tropical Andean birds

1. Life history theory postulates that physiological traits, such as energy metabolism, can be understood in terms of allocation trade-offs between self-maintenance and reproduction over an organism’s lifespan, and data show that metabolic intensity and survival vary inversely with latitude, with tropical birds exhibiting a ‘slow’ pace of life relative to temperature species. However, tropical regions harbor strong environmental gradients of their own, and it remains to be shown whether similar life history trade-offs between metabolism and longevity are reflected among tropical birds of the same latitude. 2. We estimated apparent annual survival in 37 species of tropical passerine birds along an elevational gradient (400–3000 m) in Peru to test whether variation in survival was influenced by basal metabolic rate (BMR; estimated at the same sites), elevation or both factors. We used path analysis to test our prediction that survival would decline as BMR increased, while accounting for t...