Data from a 4-year study of wing-feather mites on passerines in Portug
al (Behnke et al. 1995. Exp. Appl. Acarol. 19: 443-458) were used to i
nvestigate whether avian body mass influences the abundance of mites.
When 17 host species were used as statistically independent observatio
ns, the mite infestation score correlated positively with avian body m
ass. This correlation is not a phylogenetic artefact, having been also
found when avian phylogeny was controlled for. Three non-exclusive hy
potheses might explain this finding: (1) larger birds may provide larg
er ''habitat islands,'' enabling more mites to coexist; (2) larger bir
ds may provide more topographic refugia for mites to evade host preeni
ng; (3) larger birds may provide greater longevity of habitat islands,
thus reducing the decimating effects of transmission.