Photos of an American Oystercatcher feeding in an oyster reef near low tide.
Olympus OM-D E-M1 Mark II camera, 300mm f/4 IS Pro Lens + 1.4x teleconverter 1/2000 sec at f/5.6, ISO 400
The same camera settings were used for all the images shown in this blog entry.
American Oystercatchers feed mostly on saltwater bivalve mollusks, including many species of clams and several oysters and mussels (source).
When feeding on oysters, they locate food visually, wading slowly through slightly submerged oyster reefs until they see one that is slightly open (source).
“When a bivalve with open valves is located, the oystercatcher quickly inserts its knife-like bill into the open valves, and with several quick thrusts severs the adductor chain that holds the two valves together. The bird then extracts and consumes the soft parts”. Source
Look closely at the two images above and you can see the food that was extracted from the oyster shell.