Tropical birds are often longer-lived than their temperate counterparts, and this difference is thought to have wide-ranging consequences for reproductive strategies and demography. A prominent hypothesis for why this pattern exists is the pace-of-life hypothesis. This idea states that long life is due to low metabolic rates which result in reduced production of reactive oxygen species and lower levels of oxidative damage compared with short-lived relatives.
I'm attempting to test this hypothesis in collaboration with Dr. Blair Wolf and Dr. Thomas Martin by measuring resting metabolic rates in communities of passerine birds at tropical and temperate sites where annual survival rates of many species are known from Dr. Martin's long-term work.