You are here:
MERCURY IN AN INSECTIVOROUS BIRD SPECIES
Citation:
ADAIR, B., S. T. MCMURRY, K. D. REYNOLDS, AND G. P. COBB. MERCURY IN AN INSECTIVOROUS BIRD SPECIES. Presented at 8th International Conference on Mercury as a Global Pollutant, Madison, WI, August 06 - 11, 2006.
Description:
Mercury distributions within ecosystems must be examined to determine exposure and risk to wildlife in specific areas. In the current study, we examined exposure and uptake of mercury in nestling prothonotary warblers (protonitaria citrea) inhabiting two National Priority List (NPL) sites and a reference site. We identified prey items by collecting food directly from nestlings using esophageal constriction to accurately identify prey items. Food samples consisted of lepidopteron larvae, diptera, ephimeraoptera, and arachnids. To determine mercury exposure and uptake in nestlings from food, we analyzed food and kidney samples using a micro digestion technique developed in our lab. Further examination of Hg concentrations in food by prey type revealed that arachnids had significantly higher Hg concentrations than other prey regardless of sampling location (p<0.05). Therefore, bioaccumulation factors (BAFs) often used to examine uptake were not effective because of the large Hg variability in pooled food samples. Significant differences among the site mean Hg concentrations in tissues and food were similar (Hg at site1>site 2>reference site, p<0.05), but we wanted more detailed information. When we used geographical information systems (GIS) to describe Hg distributions, we got the same results as more intensive studies using telemetry and home range data without the time and expense. Soil Hg concentrations from previous studies were used with kidney and food Hg in partial correlation analysis resulting in significant correlations between Hg in soil and kidney (r=0.68, p<0.001) and soil and food (r=0.37, p=0.002). Correlations between food and kidney Hg were not significant (r=-0.015, p=0.93). Correlations with Hg in food samples without arachnids were more descriptive (r=0.426, p=0.041) for Hg in soil, but Hg in kidneys still did not correlate well with food (r=-.202, p=0.607).