Concentrations of Heavy Metals in American Woodcock Harvested in Connecticut

Abstract

The American woodcock is an important migratory species to both consumptive and nonconsumptive users throughout the species range. Woodcock populations have been declining steadily since surveys began in 1968. Laboratory and field studies have demonstrated several adverse effects associated with metals in other species, which has led to their inclusion as potential contributing factors to the woodcock population decline. We investigated the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), and selenium (Se) in pectoral muscle (n = 100), livers (n = 108), and kidneys (n = 104) and Pb in wing bones (n = 53) from woodcock harvested in Connecticut. Cd concentrations were elevated in 99% of woodcock livers and kidneys; 30% of kidneys were above 100 μg/g dry weight, a Cd level of reported adverse tissue and reproductive effects in other species. Hg and Cr concentrations were below current biologically significant thresholds. Asc, Pb, and Se in soft tissues were associated with lead shot use in collection. Se in 24% of livers was above 10 μg/g dry weight, the reported threshold for avian health. Wing-bone Pb was elevated above 20 μg/g in 61% of adults and 23% of juveniles examined. Our findings indicate that woodcock are being exposed to potentially damaging levels of at least two metals with known effects in other species.

Hunting with lead ammunition is not sustainable: European perspectives

“…There is also a growing body of strong evidence showing that lead gunshot has wider consequences than formerly appreciated for multiple bird species (as reviewed by Watson et al 2009;Delahay and Spray 2015). For instance, food chain linkage has been found in North America between the earthworm-eating North American Woodcock Scolopax minor and lead gunshot, and it is possible that Woodcock S. rusticolor in Europe are similarly exposed to lead in their diet (Scheuhammer et al 1998(Scheuhammer et al , 2003Hiller and Barclay 2011;Lead Ammunition Group 2015). Avian scavengers, notably eagles, buzzards, kites and vultures are poisoned having consumed meat from animals with elevated tissue lead levels, or containing either lead gunshot or fragments of lead rifle bullets (Scheuhammer and Norris 1995;Pain et al 1997;Krone et al 2009;Gangoso et al 2009;Hunt 2012;Berny et al 2015;Ecke et al 2017;Gil-Sánchez et al 2017).…”

Relationships between stomach content and concentrations of essential and non-essential elements in tissues of omnivorous nestling rooksCorvus frugilegus: Is the size and composition of stomach content relevant?

“…In spite of the huge number of papers on the accumulation of nonessential metals in wildlife, researchers have rarely linked the level of toxic metals or other contaminants to features of the environment, including the level of contaminants in various diet items (Lebedeva 1997, Fritsch et al 2012, Schipper et al 2012. Birds that feed on soil invertebrates in agricultural land are especially likely to ingest high doses of nonessential elements, mainly cadmium (Pinowski et al 1983, Carpene et al 2006, Roodbergen et al 2008, Hiller & Barclay 2011, Fritsch et al 2012, Schipper et al 2012). In the 20 th century, agricultural activity caused an apparent increase of environmental pollution, especially in the concentration of non-essential elements and agrochemicals in arable topsoil.…”