Figure 6

Antibody levels of two northern pintails at two timepoints. The bird with band # 1196-13442 was recaptured after 375 days and the bird with band # 1196-13448 was recaptured after 191 days. Dotted lines connect original capture and recapture values to show the change in antibody levels; these do not represent linear regressions as we do not know if or when they were re-infected with AIV between the sampling events. The vertical line at an S/N ratio of 0.5 represents the threshold value used to classify seropositivity, with a line at 0.7 also shown as the threshold occasionally used for this assay in other studies.