Figure 3
Relationship between hemagglutination titre score and body mass index. Each symbol represents one observation (nestling). Colour represent parental pair morph combination (pair morph): black symbols are offspring produced by like-morphs, grey symbols offspring of mixed-morph parents. Circles are female nestlings, triangles males. Trend line is the linear regression of hemagglutination and the body mass index (y = 0.002x + 0.006, R2 = 0.019). The hemagglutination titre values were scaled and centred to the mean of the year.
