Immunocompetence of young (i.e., nestlings) is positively related to
parasite virulence, as measured by parasite-induced mortality incurred
by nestlings for (a) raw data (r =
0.94, P < 0.0001, n = 13)
because mass is nonsignificant (rP =
0.33, P = 0.3, n = 13) and
(b) corrected for possible phylogenetic effects using
independent contrasts and body mass (rP
= 0.89, P < 0.0001, n = 12).