John Shaw / Purple gallinule (Porphyrio martinicus) reaches for giant bulrush (Schoenoplectis californicus) seeds. Wakodahatchee Wetlands, Florida, USA, April.

Guy Edwardes / Allen's / Lesser gallinule (Porphyrio alleni) walking on waterlilies, Chobe River, Botswana.

Melvin Grey / Purple gallinule (Porphyrula martinica) adult. Wakodahatchee Wetlands, Florida, USA, May.

George Sanker / Purple gallinule (Porphyrula martinica) in mangrove swamp. Everglades National Park, Florida, USA. March.

Tui De Roy / Takahe (Porphyrio hochstetteri) family in large breeding pen, Burwood Breeding Center, New Zealand

George Sanker / Purple gallinule (Porphyrio martinica) moving across waterlily leaves, Everglades National Park, Florida, USA, April

George Sanker / Purple gallinule (Porphyrio martinica) moving across waterlily covered surface, Everglades National Park, Florida, USA, March

Donald M. Jones / Purple Gallinule (Porphyrio martinicus), Everglades National Park, Florida

Rolf Nussbaumer / American purple gallinule {Porphyrio martinicus} eating Yellow Water Lily flower {Nuphar lutea}Welder Wildlife Refuge, Sinton, Texas, USA.

Rolf Nussbaumer / American purple gallinule {Porphyrio martinicus} adult on Yellow Water Lily pads {Nuphar lutea} Welder Wildlife Refuge, Sinton, Texas, USA.

Tom Vezo / Purple gallinule {Porphyrio martinicus} perched in a tree Florida, USA Everglades National Park Florida

Tom Vezo / Purple gallinule {Porphyrio martinicus} on a water lily in Florida, USA Everglades National Park, Florida

Tom Vezo / American purple gallinule. (Porphyrio martinicus) Florida Everglades, USA.

Mitsuaki Iwago / Purple Gallinule (Porphyrio martinicus) walking across lily pads, North America

Pedro Narra / Purple swamphen (Porphyrio porphyrio). Sado Estuary Natural Reserve, Portugal. December.

George Sanker / Purple gallinule (Porphyrio martinicus) feeding on Lily (Nymphaeaceae) flower. Everglades National Park, Florida, USA. March.

George Sanker / Purple gallinule (Porphyrio martinicus) walking on Lilies (Nymphaeaceae). Everglades National Park, Florida, USA. March.

George Sanker / Purple gallinule (Porphyrio martinicus) striding over Lily (Nymphaeaceae) pads. Everglades National Park, Florida, USA. March.

George Sanker / Purple gallinule (Porphyrio martinicus) striding over Lily (Nymphaeaceae) pads. Everglades National Park, Florida, USA. March.

George Sanker / Purple gallinule (Porphyrio martinicus) feeding on Lily (Nymphaeaceae). Everglades National Park, Florida, USA. March.

Pedro Narra / Western swamphen (Porphyrio porphyrio) Sado estuary, Portugal. April

Pedro Narra / Purple swamphen (Porphyrio porphyrio) profile, Sado Estuary, Portugal. December

Sandesh Kadur / Purple swamphen (Porphyrio madagascariensis) in wetland. Lake Manyara National Park, Tanzania.

Andy Trowbridge / Purple Swamphen / Pukeko (Porphyrio porphyrio) searching for food along lake edge. Christchurch, New Zealand. July.

Sebastian Kennerknecht / Grey-headed Swamphen (Porphyrio poliocephalus) female, Diyasaru Park, Colombo, Sri Lanka

Barry Mansell / Purple gallinule (Porphyrula martinica) hunting amngst lily pads, Florida, USA, May.

Barry Mansell / Purple Gallinule (Porphyrula martinica) on lily pads with snail in beak, North Florida,USA

Mike Read / Purple swamp-hen (Porphyrio porphyrio) feeding on mat of vegetation, Quinta do Lago, Ria Formosa Nature Reserve, Algarve Portugal, February.

Andy Trowbridge / Pukeko (Porphyrio porphyrio) searching for food along lake edge. Christchurch, New Zealand, July

Oriol Alamany / Purple swamphen (Porphyrio porphyrio), Lord Howe island, Lord Howe Island Group UNESCO Natural World Heritage Site, New South Wales, Australia

Julian Hume / Reunion blue gallinule (Porphyrio caerulescens) Extinct c.1700. Endemic to Reunion Island, Mascarenes.

Mark Carwardine / Takahe (Porphyrio hochstetteri) translocated population as part of conservation project, Tiritiri Matangi, North Island, New Zealand. Endangered species, November 2011

Richard Du Toit / Purple gallinule (Porphyrio porphyrio)feeding, South Africa

Hanne & Jens Eriksen / Purple swamphen (Porphyrio porphyrio) Oman, October

Juergen & Christine Sohns / Purple Gallinule (Porphyrio martinicus), Wakodahatchee Wetlands, Delray Beach, Florida

Mark Carwardine / Takahe (Porphyrio hochstetteri), Tiritiri Matangi Island, North Island, New Zealand

Mark Carwardine / Takahe (Porphyrio hochstetteri) chick, Tiritiri Matangi Island, North Island, New Zealand

Alan Murphy/ BIA / Purple Gallinule (Porphyrio martinicus), Florida

Richard Du Toit / Purple gallinule (Porphyrio porphyrio) in flight, Marievale Bird Sanctuary, Gauteng Province, South Africa, September.

Paul Hobson / Purple Gallinule (Porphyrio martinicus) on lilypad, Florida, USA, February.

Tim Zurowski / Purple Gallinule (Porphyrio martinicus), Florida

Tim Zurowski / Purple Gallinule (Porphyrio martinicus) foraging, Florida

Hanne & Jens Eriksen / Purple swamphen (Porphyrio porphyrio) walking on lily pads (Nymphaeaceae), Thailand, February.

Tui De Roy / Takahe (Porphyrio hochstetteri) pair in large breeding pen, Burwood Breeding Center, New Zealand

Tui De Roy / Takahe (Porphyrio hochstetteri) feeding on grass shoots, Burwood Breeding Center, New Zealand

Tui De Roy / Takahe (Porphyrio hochstetteri) in large breeding pen, Burwood Breeding Center, New Zealand

Ashish & Shanthi Chandola / Purple swamphen (Porphyrio poliocephalus), Boondala Bird Sanctuary, Sri Lanka.

Tui De Roy / Takahe (Porphyrio mantelli) eating grass, Tiritiri Mantangi Island Scientific Reserve, New Zealand. Endemic.

Tui De Roy / Takahe (Porphyrio mantelli) eating grass, Tiritiri Mantangi Island Scientific Reserve, New Zealand. Endemic.

Richard Du Toit / Purple Gallinule (Porphyrio porphyrio) on reeds, Marievale Bird Sanctuary, Gauteng Province, South Africa, August.

Richard Du Toit / Purple Gallinule (Porphyrio porphyrio) Rietvlei Nature Reserve, Gauteng Province, South Africa, April.

Brent Stephenson / Adult Takahe (Porphyrio hochstetteri) closeup showing the massive bill and frontal shield as it walks through grassland. Tiritiri Matangi Island, Auckland, New Zealand, February. Endangered species.

Brent Stephenson / Adult Takahe (Porphyrio hochstetteri) closeup showing the massive bill and frontal shield. Tiritiri Matangi Island, Auckland, New Zealand, April. Endangered species.

XI ZHINONG / Purple swamphen (Porphyrio porphyrio) in flight, China, March.

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Bueng Boraphet, Thailand

David Tipling / Takahe (Porphyrio mantelli) portrait, Tiri Matangi, North Island, New Zealand.

Lou Coetzer / Allen's gallinule (Porphyrio alleni) on water lily pads, Chobe River, Botswana, May.

Lou Coetzer / Allen's gallinule (Porphyrio alleni) standing on water lily leaf, Chobe River, Botswana, May.

Lou Coetzer / Allen's gallinule (Porphyrio alleni) walking over water lily pads, Chobe River, Botswana, May.

Greg Oakley / Purple Swamphen (Porphyrio porphyrio) wading, Victoria, Australia

Greg Oakley / Purple Swamphen (Porphyrio porphyrio) wading, Victoria, Australia

George Sanker / Purple Gallinule (Porphio martinica) in mangrove swamp. . Everglades National Park, Florida, USA, March.

George Sanker / Purple Gallinule (Porphio martinica) in mangrove swamp. Everglades National Park, Florida, USA, March.

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Victoria, Australia

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Victoria, Australia

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Victoria, Australia

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Victoria, Australia

Rob Drummond / Purple Swamphen (Porphyrio porphyrio), Victoria, Australia

Bob Steele / Purple Swamphen (Porphyrio porphyrio), Bung Boraphet, Thailand

Robert Royse / Purple Gallinule (Porphyrio martinicus), Florida

Robert Royse / Purple Gallinule (Porphyrio martinicus), Florida

Patrick Donini / Purple Swamphen (Porphyrio porphyrio), Yanchep National Park, Australia

Glenn Bartley / Purple Gallinule (Porphyrio martinicus) juvenile, Ecuador

Jiri Slama / Purple Swamphen (Porphyrio porphyrio), Florida

Oscar Diez / Purple Swamphen (Porphyrio porphyrio), Andalucia, Spain

Oscar Diez / Purple Swamphen (Porphyrio porphyrio), Andalucia, Spain

Oscar Diez / Purple Swamphen (Porphyrio porphyrio), Andalucia, Spain

Ralph Martin / Purple Swamphen (Porphyrio porphyrio), Mallorca, Spain

Christine Jung / Purple Swamphen (Porphyrio porphyrio), Mallorca, Spain

Jan Wegener / Purple Swamphen (Porphyrio porphyrio), Australia

Jan Wegener / Purple Swamphen (Porphyrio porphyrio) standing on nest, Australia

Sebastian Kennerknecht / Takahe (Porphyrio hochstetteri) grazing, Kapiti Island, North Island, New Zealand

Sebastian Kennerknecht / Purple Swamphen (Porphyrio porphyrio) grazing, Nga Manu Nature Reserve, North Island, New Zealand

Roland Seitre / Purple swamphens (Porphyrio porphyrio) Noumea, North Province, New Caledonia.

Ernie Janes / Purple Swamphen (Porphyrio porphyrio) in wetland, Sri Lanka

Laurent Geslin / Purple swamphen (Porphyrio porphyrio) Keoladeo Ghana NP, Bharatpur, Rajasthan, India

Juergen Freund / Purple Swamphen (Porphyrio porphyrio) in the wetlands of Muloorina Station near Lake Eyre South, South Australia, Australia

David Tipling / Takahe (Porphyrio hochstetteri) Tiri Matangi Island - an island which is being repopulated with birds, North Island, New Zealand

George Sanker / American Purple Gallinule (Porphyrio martinica) displaying brightly coloured wings. Everglades National Park, Florida, USA, March.

Juan Manuel Borrero / Illustration of Purple Gallinule (Porphyrio porphyrio). Pencil and watercolor painting.

Andrew Walmsley / Pukeko (Porphyrio porphyrio melanotus) pair mating. Christchurch, New Zealand, October. Sequence 3 of 3.

Andrew Walmsley / Pukeko (Porphyrio porphyrio melanotus) pair mating. Christchurch, New Zealand, October. Sequence 2 of 3.

Andrew Walmsley / Pukeko (Porphyrio porphyrio melanotus) pair mating. Christchurch, New Zealand, October. Sequence 1 of 3.

Andrew Walmsley / Pukeko (Porphyrio porphyrio melanotus) attempting to mate. Christchurch, New Zealand, October.

Andrew Walmsley / Pukeko (Porphyrio porphyrio melanotus). Christchurch, New Zealand, October.

Mark Carwardine / Takahe (Porphyrio mantelli) Burwood Bush Takahe Rearing Unit, near Te Anua, New Zealand, Endangered species