HOLE IN ONE: SHOREBIRD PREDATION TRACES BELICHNUS MONOS ON RECENT ATLANTIC SURF CLAM SHELLS

Irregular openings on Atlantic surf clam valves (Spisula solidissima; length: 10-15 cm; n=30) have the inner peeling area, which indicates an impact from the outside. Analysis of the damage metrics (peel diameters and trace position) indicates that these are consistent with a predation trace Belichnus monos. Openings were confined to a relatively small region in the center of the valve as indicated by size-independent ratios of anterior/posterior and dorsal/ventral metrics. This suggests that the trace makers, likely shorebirds, have a preferred predation tactic for disabling the prey, followed by consumption of internal organs by prying the valves. The latter leaves diagnostic chipmarks along the ventral edge. Our approach demonstrates that size-independent metrics offer a rapid and effective means of quantifying Belichnus isp. and other traces (e.g., Oichnus isp.) on bivalves.