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Size and mass of grit in gizzards of sandhill cranes, tundra swans, and mute swans

January 1, 2001

Because it has been suggested that waterbirds may ingest lost or discarded lead fishing weights as grit, we examined grit in the gizzards of Sandhill Cranes (Grus canadensis), Tundra Swans (Cygnus columbianus), and Mute Swans (Cygnus olor), three species where individuals have been poisoned by the ingestion of lead fishing weights. The greatest proportion (by mass) of grit in gizzards of Sandhill Cranes consisted of particles with a minimum dimension of 2.36-4.75 mm. Grit particles in swans were much smaller, with the most prevalent (by mass) being 0.6-1.18 mm. The greatest dimension of the largest grit particle found in cranes and swans was 17.4 mm and 14.0 mm, respectively. The U.S. Environmental Protection Agency has proposed a ban on lead fishing weights of ≤25.4 mm in any dimension. Based on the size of grit particles that we found in gizzards of Sandhill Cranes, Mute Swans, and Tundra Swans, we believe it is unlikely that individuals of those species would ingest, as grit, lead fishing weights larger than 25.4 mm in any dimension.

Citation Information

Publication Year 2001
Title Size and mass of grit in gizzards of sandhill cranes, tundra swans, and mute swans
DOI 10.2307/1522036
Authors J. Christian Franson, Scott P. Hansen, Adam E. Duerr, Stephen DeStefano
Publication Type Article
Publication Subtype Journal Article
Series Title Waterbirds
Series Number
Index ID 70006595
Record Source USGS Publications Warehouse
USGS Organization National Wildlife Health Center

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