Mean blood and first primary feather (P1) mercury concentrations (ppm ww and fw, respectively) for Nelson's Sparrows captured near Grand Forks, ND over three breeding seasons.

Captures are divided into those that occurred within (In) the drainage basin for Kellys Slough National Wildlife Refuge and those that occurred outside of this basin (Out). Tissue mercury data for these two groups of captures were compared using generalized linear models (proc glm) with Tukey-Kramer multiple comparisons. P-values following each tissue mercury column are the results of these comparisons.