flock of red knots (calidris canutus) off bull island, dublin, commonly found along coasts

flock red knots calidris canutus shorebirds migratory birds birdwatching bull island dublin coastal nature wildlife feeding invertebrates habitat wader bird ireland beach sandbar environmental conservation seabirds migration wetland reserve shore sandpipers species outdoor birding endangered sand ocean route mudflat ecosystem protection animal behavior flocks efforts