The Curlew Sandpiper (Calidris ferruginea) has a long, black bill with a down-curved end and black legs and feet. In breeding plumage, it is bright reddish brown below and the wings are barred black. In its non-breeding plumage, it is grey-brown above, white below, with a white wing bar visible in flight. It has a long, black bill with a down-curved end and black legs and feet. The curlew sandpiper is highly gregarious, and will form flocks with other calidrid waders, particularly dunlin. It forages in soft mud on marshes and the coast, mainly picking up food by sight. It mostly eats insects and other small invertebrates.