A study of population size, survival, longevity, and movement in Biscutate Swift populations in southern Brazil estimated mean annual survival for the species to be 0.88, with an average lifespan of 18 years. Subadult survival was not estimated, but first-year breeders consistently weigh less, likely due to some type of food stress. Survival rate at this stage is thus expected to be lower than average. Between the four colonies studied, few intercolonial movements occurred, and migration did not take place in these populations. Lack of migratory movement was attributed to constant year-round food availability (Pichorim et al. 2010).