Mercury (Hg) is a potent neurotoxin that biomagnifies within food webs. Adverse effects have been documented for avian species related to exposure of elevated Hg levels. High elevation, boreal forests generally receive higher atmospheric Hg deposition and regional studies have subsequently identified elevated blood Hg concentrations in songbird species inhabiting these montane habitats. The overall goal of this study was to investigate spatial and seasonal Hg exposure patterns in songbird species along an elevational gradient on Whiteface Mountain in the Adirondack Park of New York State. Songbird blood samples were collected from June–July in 2009 and 2010 along an elevational gradient at 13 study plots (450–1400 m) with a focus on Catharus thrushes, including the hermit thrush, Swainson’s thrush, and Bicknell’s thrush. The main results of this study documented: (1) an overall linear pattern of increasing blood Hg concentrations with increasing elevation, with additional analysis suggesting a nonlinear elevational pattern of increasing blood Hg concentrations to 1075 m, followed by decreasing concentrations thereafter, for all Catharus thrush species across the elevational gradient; and (2) an overall nonlinear seasonal pattern of increasing, followed by decreasing blood Hg concentrations across target species. Avian exposure patterns appear driven by elevated atmospheric Hg deposition and increased methylmercury bioavailability within high elevation habitats as compared with low elevation forests. Seasonal patterns are likely influenced by a combination of complex and dynamic variables related to dietary selection and annual molting cycles. Considering that few high elevation analyses have been conducted within the context of regional songbird research, this project complements the results from similar studies and highlights the need for further monitoring efforts to investigate environmental Hg contamination within avian communities.

汞（Hg）是一种有效的神经毒素，可在食物网中生物放大。业已证明与汞暴露升高有关的鸟类有害作用。高海拔的北方森林通常会吸收较高的大气Hg沉积物，区域研究随后发现居住在这些山地栖息地的鸣禽物种中的血液Hg浓度升高。这项研究的总体目标是调查位于纽约州阿迪朗达克公园的怀特菲斯山沿海拔梯度的鸣禽物种中的空间和季节性汞暴露模式。从2009年6月至7月和2010年6月至7月期间，以高度梯度采集了13个研究地块（450-1400 m）上的歌鸟血样，重点是凯撒路（Catharus）鹅口疮，包括隐士鹅口疮，斯温森氏鹅口疮和比克内尔鹅口疮。这项研究的主要结果证明：（1）对于所有的Catharus，血液Hg浓度随海拔升高而增加的总体线性模式，另外的分析表明，血液Hg浓度至1075 m呈非线性升高模式，其后降低浓度。跨越海拔梯度的画眉类 （2）整个目标物种的血液Hg浓度下降的总体非线性季节性模式，然后是下降。与低海拔森林相比，高海拔栖息地内大气汞的沉积增加和甲基汞生物利用度的增加是鸟类接触禽类的原因。季节性模式可能受与饮食选择和年度换羽周期有关的复杂和动态变量的组合影响。考虑到在区域鸣禽研究的背景下很少进行高海拔分析，因此该项目对类似研究的结果进行了补充，并强调需要进一步监测努力以调查禽类社区内环境汞污染。