Sélection des proies par quatre espèces d'oiseaux limicoles (Charadrii) de passage dans l'estuaire du Saint-Laurent lors de la migration vers le sud

The diet of four shorebird species, the Black-bellied Plover (Pluvialis squatarola), Semipalmated Plover (Charadrius semipalmatus), Lesser Yellowlegs (Tringa flavipes), and Semipalmated Sandpiper (Calidris pusilla), was studied on an intertidal mudflat during their southward migration. Mollusks dominate the invertebrate fauna in the feeding area, representing 95% of the organisms in terms of number and biomass. The predatory shorebirds appeared to forage selectively on polychaetes and crustaceans, which represent only 5% of the benthic invertebrates in the feeding area. Lesser Yellowlegs eat nearly exclusively crustaceans. The other three predators feed mainly on Nereis virens and all three select groups of worms that differ significantly by their size, the larger predators consuming the biggest prey. Despite the simultaneous presence of the four predators on the feeding area, they seem to share the resources without overt interspecific competition.