Gabriel Rojo / Greater rhea (Rhea americana) nest with many eggs, at edge of arable field. Patagonia, Argentina. October.

Ingo Arndt / Hummingbird (Trochilidae) egg and Ostrich (Struthio camelus) egg, a size comparison of eggs of world's smallest and largest extant birds. Senckenberg Museum, Frankfurt, Germany.

Suzi Eszterhas / Three Ostrich (Struthio camelus) females sitting in grass, Sabi Sands, South Africa

Angelo Gandolfi / Greater rhea (Rhea americana), three feeding on agricultural land. Brazil.

Angelo Gandolfi / Greater rhea (Rhea americana), six walking across grassland. Cerrado, Brazil.

Franco Banfi / Greater rhea (Rhea americana) Pantanal wetlands, Mato Grosso, Brazil

David Perpinan / Rhea (Rhea americana) arriving at nest and settling on eggs, Pantanal, Mato Grosso do Sul, Brazil.

David Perpinan / Rhea (Rhea americana) incubating eggs, Pantanal, Mato Grosso do Sul, Brazil.

Franco Banfi / Greater rhea (Rhea americana) Pantanal wetlands, Mato Grosso, Brazil

Luke Massey / Rhea (Rhea americana) chicks, Pantanal, Brazil.

Luke Massey / Rhea (Rhea americana) chicks, Pantanal, Brazil.

Luke Massey / Rhea (Rhea americana) male with his chicks, Pantanal, Brazil.