See more from this Division: General Discipline Sessions
See more from this Session: Paleontology IV - Exceptional Preservation and Taphonomy
Abstract:
Two taxa, Western Gulls (Larus occidentalis) and Northwestern Crows (Corvus caurinus) were observed utilizing shell-dropping on hard substrata to obtain food. Western Gulls were observed to pick up shallow-burrowing, mid-sized bivalves in their beaks from various intertidal substrates and drop them on exposed intertidal gravel bars. Northwestern Crows were observed to obtain bivalves from the upper intertidal and drop them on hard substrates (logs, gravel, cement) above the high tide line.
Avian predation activity by both bird taxa resulted in cross-facies transport of bioclastic material. As well as shell breakage of resident infaunal bivalves on intertidal gravel flats, predation activity by these birds resulted in significant cross-facies shell transport. This included transport of bivalves from sand-dominated intertidal flats to those characterized by gravel or cobble substrata by Western Gulls as well as transport to supratidal and intervals well above the maximum high tide line by Northwestern Crows.
Shorebird-generated intertidal shell accumulations have significant implications in the analysis of ancient shell accumulations, particularly those in late Mesozoic and Cenozoic to recent successions.
See more from this Division: General Discipline Sessions
See more from this Session: Paleontology IV - Exceptional Preservation and Taphonomy