Corticosterone hormone as an indicator for environmental mercury stress in migratory versus resident bird species


The goal of this project is to learn more about how migration affects a bird’s reaction to environmental mercury stress. I will be measuring corticosterone (CORT), a stress hormone, as well as mercury in feather samples from a migratory and nonmigratory species. I expect that nonmigratory species will exhibit more mercury but less CORT in their feathers. The constant exposure will naturally select birds that do not overreact to mercury poisoning. Overreaction to mercury tends to lead to reduced reproductive success. Therefore, it acts as a direct selective pressure on birds in mercury-polluted environments. With this information, we can learn more about how mercury pollution in one area affects wildlife on a continental scale.

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Investigating Developmental Delay in Model Songbirds Due to Methylmercury Exposure – Abstract

Mercury is prevalent in aquatic and terrestrial food webs and has wide-ranging detrimental effects on both wildlife and human populations (Gerson et al., 2018). Current and previous studies suggest that long-term, low level exposure to methylmercury (around 1.2 ppm) is associated with a wide variety of deleterious effects on zebra finch populations. These studies have shown reduced fitness, immune response, metabolic scope, and more in the songbirds after exposure to low levels of mercury (Whitney et al., 2017; Paris et al., 2018). The mechanisms underlying these effects however, remain unknown. I have already begun research on the effects of mercury on the development of songbird embryos and have found that the mercury exposed embryos seemed to lack some of the key developmental markers that appeared in control embryos of the same age. Based on my preliminary data, I hypothesize that mercury induces developmental delay and impeded brain development in zebra finches due to a synergistic effect of misregulation of cell-fate patterning and cell proliferation genes, leading to misregulation of genes expressed later in the song regions of the brain. If supported, this hypothesis predicts clear differences in gene expression in both cell proliferation assays (PCNA) and neural patterning genes (Sox2, NBT) compared to unexposed control embryos. I predict that the early delays and misregulation will then affect downstream genes affecting song learning (specifically the FoxP2 gene). Over the summer, I plan to continue to collect data in order to complete my data set, conduct specific molecular assays to test my working hypothesis. Following in situ hybridization, I will perform histology to assess spatial expression patterns in detail. To obtain quantitative data, in addition to the in situ hybridization experiments, I will also perform RT-PCR on these genes and correlate results with the spatial expression data. Taken together, the data emerging from these studies will test the hypothesis that developmental delay is due to a synergistic effect of misregulation of cell-fate patterning and an inhibition of cell proliferation, and that genes expressed later in the song regions will in turn be misregulated. If my results do not support this hypothesis it will be equally interesting because it will suggest that these neurological phenotypes are due to other pathways or occur later in development.

An Afternoon with Audubon – Winterthur Week 9

Most of this last week was spent playing the print block matching game – figuring out which blocks create each print, and updating Registration’s records of those prints. Going through the prints took up most of my time, to the point where looking at prints left me feeling slightly sick, because they were all I ever saw, day in, day out.

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The Effects of Timing and Duration of Mercury Exposure on Beak Redness in Zebra Finches


My name is Rebecca Gilson and I’m a rising senior here at William & Mary.  I’m a biology major with a history minor. I’m planning to apply to and attend Veterinary School after I graduate.  This summer I’ll be working in Dr. Cristol’s lab looking into the effects of mercury on zebra finches.

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A new look at your backyard birds: what are they really worth?


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