Abandoned Seabird Eggs as a Calcium Source for Terrestrial Gastropods

Alexander L. Bond, Antony W. Diamond


Birds’ use of terrestrial gastropods to supplement calcium for egg formation has been well documented, but the reverse, gastropods using avian eggshells as a calcium source, has not been recorded previously. We collected Arctic Tern, Sterna paradisaea, eggs, abandoned in July 2006, that were found to have many terrestrial gastropods on the surface, and it appeared as though the outer eggshell layers were removed. Using scanning electron microscopy, we compared “grazed” and “ungrazed” sections of the same shell with eggshells collected in 2005 that were not attended by snails. It appears as though the snails removed the outer eggshell layers, presumably to supplement their own shell growth.


Arctic Tern; Sterna paradisaea; White-lip Gardensnail; Cepaea hortensis; Glossy Pillar; Cionella lumbria; calcium; eggshell; New Brunswick

Full Text:


DOI: http://dx.doi.org/10.22621/cfn.v121i4.521

Volumes that are more than six years old are freely available courtesy of the Biodiversity Heritage Library.


Questions or problems with the website? Contact William Halliday (info -at- canadianfieldnaturalist -dot- ca).