Invasive House Sparrows Are Helping Scientists Detect Dangerous Contaminants
March 16, 2026
The house sparrow is a highly invasive pest in North Carolina, and bluebird enthusiasts frequently throw their eggs out and remove their nests to keep them from overtaking the nest boxes that bluebirds call home.
A new study puts those discarded eggs to use in detecting heavy metal contaminants in bluebird habitats, which often border human communities.
To collect the eggs, researchers reached out to bluebird watchers through Sparrow Swap, a cooperative program between North Carolina State University and the N.C. Museum of Natural Sciences that provided volunteers with equipment to store and send in house sparrow eggs. The program allowed researchers to obtain valuable information from eggs that would otherwise be destroyed and discarded.
Aubrey Wiggins — a co-author on the study, a former volunteer with Sparrow Swap, and current technician in the Museum’s herpetology lab and collections — weighed, measured and photographed nearly 2,000 of those house sparrow eggs during the summers of 2016–18.
“Student interns eventually used a tailored program to analyze the spot and speckle patterns of the eggs I’d photographed in an effort to tie those patterns to persistent environmental contaminants that were detected in the eggs through chemical analysis,” he explained.
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