The Semipalmated Sandpiper (Calidris pusilla) is an Arctic-breeding shorebird that undergoes a long-distance fall migration to wintering grounds in South America. Much of the population is thought to complete this migration with a single stop in the Bay of Fundy, Canada. While in the region, these birds feed extensively on infaunal prey found on intertidal mudflats.
Earlier morphological analysis of stomach contents had led researchers to believe that Semipalmated Sandpipers in the Bay of Fundy rely on an amphipod species called Corophium volutator as their major food source. However, a new study by researchers of the University of New Brunswick shows that the sandpipers' diet is far more general than previously thought.
The colleagues used molecular scatology through metabarcoding, in other words they used Next Generation Sequencing to barcode carefully selected and sampled bird droppings.
The results show that the birds also feed on freshwater insects that wash down onto the beach in streams, eggs of ocean-going fish deposited on the shore by tides, and organisms that live in the beach's intertidal zone, among those Corophium volutator. This broader diet may increase their exposure to pesticides and other toxins, in addition to making the birds more resilient to changes in their habitat, such as those due to climate change.
Current Semipalmated Sandpiper conservation efforts in the Bay of Fundy focus on beach and intertidal habitats, neglecting terrestrial, pelagic, and freshwater systems that may not only supply nutrients, but harmful chemicals or pesticides as well. Future studies need to explore this possibility, attempting to determine if bioaccumulation of harmful toxins from multiple ecosystems in the Semipalmated Sandpipers are having any negative impacts upon this species.