Results
There was no significant correlation between fuel stores and microbial
killing ability (Table 1, Figure 1) or IgY levels (Table 2, Figure 1) in
any of the four species. However, Julian day (date of capture) had a
significant negative effect on microbial killing ability in Song
thrushes and Wheatears (Figure 2, Table 1) and on IgY levels in Song
thrushes (Figure 2, Table 2), meaning birds arriving at the stopover
later in the migration season had lower microbial killing and lower IgY
levels ability than birds arriving earlier. Microbial killing ability
and IgY levels did not differ between sexes.
Table 1: The correlation test output between microbial killing ability
and fuel stores, microbial killing ability and Julian day in four
species of migrating birds during spring migration; and Wilcoxon test
output for sex differences in microbial killing ability in four species
during spring migration. P-values <0.05 are marked in bold.