Fig. 3. Elevational range in relation to body mass for extant hummingbird species. Within each size class, the box plot delineates mean interspecific values for the lower and upper elevational range, as given for each species by del Hoy et al. (del Hoy et al., 1999). The numbers within any given box indicate the number of species for the particular size class. Interspecific linear regressions relating body mass to minimum, mean and maximum elevation are highly significant (P<0.001 for each variable), although the variance in elevational distribution that can be attributed to body mass alone is less than 10% in each case.