Ardea
Official journal of the Netherlands Ornithologists' Union

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Soler J.J., Soler M., Gabriel-Martinez J. (1993) Grit ingestion and cereal consumption in five corvid species. ARDEA 81 (2): 143-149
Grit use in five corvid species has been studied in a cereal-producing plain area where cereal is an important dietary component. Grit size differed significantly between species. Almost all of the pellets examined contained grit, principally quartz. We found strong support for the hypothesis that grit helps to break down the ingested food in Jackdaws, Carrion Crows and Ravens. Only the Jackdaw and the Carrion Crow data significantly support the hypothesis that calcareous grit is a necessary source of calcium for eggshell formation. In the case of the Raven, other studies had recorded vegetable matter only rarely, and grit almost never in either stomach or pellet contents. On the basis of the grit size selection pattern found in our study, and of the lack of grit ingestion reported in other studies, we suggest that the Raven is currently adapting its diet to cereal consumption.


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