Pete Oxford / Two White faced whistling ducks {Dendrocygna viduata}, Madagascar.

Murray Cooper / Black-bellied Whistling Duck (Dendrocygna autumnalis) and White-faced Whistling-Duck (Dendrocygna viduata) flock in wetland, Colombia

Gabriel Rojo / White-faced whistling ducks (Dendrocygna viduata), La Pampa, Argentina

Eric Baccega / Nile crocodile (Crocodylus niloticus) resting with flock of white-faced whistling duck around (Dendrocygna viduata). Moremi National Park, Okavango delta, Botswana, Southern Africa

Philippe Clement / White-faced whistling duck (Dendrocygna viduata) swimming in pond, native to Africa and South America. Captive.

Gabriel Rojo / White-faced whistling duck (Dendrocygna viduata) group of three, La Pampa, Argentina.

Wim van den Heever / White-faced duck (Dendrocygna viduata) with reflection at edge of water, Zimanga Private Game Reserve, South Africa.

Bruno D'Amicis / White-faced whistling ducks (Dendrocygna viduata) swimming in wetlands, Jimba, Bahir Dar. Lake Tana Biosphere Reserve. Ethiopia

Denis-Huot / Nile crocodiles (Crocodylus niloticus) and White-faced whistling-ducks (Dendrocygna viduata) at edge of water, Mara river, Masai-Mara game reserve, Kenya.

Christophe Courteau / Roseate Spoonbill (Ajaia ajaia) and White-faced Whistling Duck (Dendrocygna viduata) taking off the shallow water of Hato El Cedral, Llanos, Venezuela.

Christophe Courteau / Mixed flock of White-faced Whistling Duck (Dendrocygna viduata), Black-bellied Whistling-duck (Dendrocygna autumnalis) and Roseate Spoonbill (Ajaia ajaia) taking off the shallow water of Hato El Cedra...

Christophe Courteau / Mixed flock of White-faced Whistling Duck (Dendrocygna viduata), Black-bellied Whistling-duck (Dendrocygna autumnalis), Black-necked Stilts (Himantopus mexicanus) taking off the shallow water of Hato...