Selective feeding behavior of birds on burrowing irregular spatangoid sea urchins, normally out of reach for such predators, is described. Behavioral observations were made on Carrion Crows (Corvus corone) feeding on spatangoid sea urchins (Echinocardium cordatum) during low tide on two different beaches in Brittany, France. The on-site searching behavior of individuals and flocks of crows on the surf line was observed together with characteristic feeding traces on the sediment. Wound morphologies on collected tests were documented with respect to possible preservation potential and recognition in the fossil record. Documented traces on feeding sites allow for clear identification of predator species and can be linked to observed bird behavior.
The two sites differ in sea urchin size and the resulting predation traces on the echinoid tests. Predation on smaller specimens fragments the test, whereas predation on larger specimens leaves a characteristic wound morphology that is mainly restricted to the aboral side of the test. The wound morphology resulting from test puncturing involves both extensive inter- and intraplate fragmentation but does not completely destroy the tests. These predation traces are compared to other observed records of bird predation on echinoids. The potential for recognition and preservation in the rock record is then discussed.