Mercury in Nelson's Sparrow Subspecies at Breeding Sites
نویسندگان
چکیده
BACKGROUND Mercury is a persistent, biomagnifying contaminant that can cause negative effects on ecosystems. Marshes are often areas of relatively high mercury methylation and bioaccumulation. Nelson's Sparrows (Ammodramus nelsoni) use marsh habitats year-round and have been documented to exhibit tissue mercury concentrations that exceed negative effects thresholds. We sought to further characterize the potential risk of Nelson's Sparrows to mercury exposure by sampling individuals from sites within the range of each of its subspecies. METHODOLOGY/PRINCIPAL FINDINGS From 2009 to 2011, we captured adult Nelson's Sparrows at sites within the breeding range of each subspecies (A. n. nelsoni: Grand Forks and Upham, North Dakota; A. n. alterus: Moosonee, Ontario; and A. n. subvirgatus: Grand Manan Island, New Brunswick) and sampled breast feathers, the first primary feather (P1), and blood for total mercury analysis. Mean blood mercury in nelsoni individuals captured near Grand Forks ranged from 0.84 ± 0.37 to 1.65 ± 1.02 SD ppm among years, between 2.0 and 4.9 times as high as concentrations at the other sites (P<0.01). Breast feather mercury did not vary among sites within a given sampling year (site means ranged from 0.98 ± 0.69 to 2.71 ± 2.93 ppm). Mean P1 mercury in alterus (2.96 ± 1.84 ppm fw) was significantly lower than in any other sampled population (5.25 ± 2.24-6.77 ± 3.51 ppm; P ≤ 0.03). CONCLUSIONS/SIGNIFICANCE Our study further characterized mercury in Nelson's Sparrows near Grand Forks; we documented localized and potentially harmful mercury concentrations, indicating that this area may represent a biological mercury hotspot. This finding warrants further research to determine if wildlife populations of conservation or recreational interest in this area may be experiencing negative effects due to mercury exposure. We present preliminary conclusions about the risk of each sampled population to mercury exposure.
منابع مشابه
Mercury in breeding saltmarsh sparrows (Ammodramus caudacutus caudacutus).
Environmental mercury exposure of birds through atmospheric deposition and watershed point-source contamination is an issue of increasing concern globally. The saltmarsh sparrow (Ammodramus caudacutus) is of high conservation concern throughout its range and the potential threat of mercury exposure adds to other anthropogenic stressors, including sea level rise. To assess methylmercury exposure...
متن کاملMercury in non-breeding sparrows of North Carolina salt marshes.
We captured Nelson's, Saltmarsh and Seaside Sparrows (Ammodramus nelsoni, A. caudacutus and A. maritimus) at three salt marsh sites near Wrightsville Beach, North Carolina during five non-breeding seasons (September through April, 2006-2011). We analyzed breast feather samples from all of these seasons and blood and first primary feather (P1) samples from three seasons (2008-2011) for mercury (...
متن کاملEcological influences on vocal development in the white-crowned sparrow.
Gambel's white-crowned sparrow, Zonotrichia leucophrys gambelii, is a long-distance migrant that, in contrast to other subspecies of white-crowned sparrow, does not form vocal dialects. I studied the process of vocal development in the field and laboratory to determine how it differed from the process in three other subspecies previously studied. Four common song types existed in a random spati...
متن کاملDistribution, Abundance, and Habitat Affinities of the Coastal Plain Swamp Sparrow
—We examined the distribution and abundance of the Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens) at previously occupied sites and points within potential habitat. We found Swamp Sparrows throughout their formerly documented range except in southern Chesapeake Bay. Swamp Sparrows were most common in the Mullica River region of New Jersey where we detected individuals at 78% of sys...
متن کاملInadvertent social information in breeding site selection of natal dispersing birds.
Several species use the number of young produced as public information (PI) to assess breeding site quality. PI is inaccessible for synchronously breeding birds because nests are empty by the time the young can collect this information. We investigate if location cues are the next best source of inadvertent social information (ISI) used by young prospectors during breeding site choice. We exper...
متن کامل