Edwin Giesbers / Male Sulawesi red-knobbed hornbill (Aceros cassidix) head portrait, captive

Tim Laman / Female Knobbed hornbill (Aceros cassidix) in flight. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male delivering figs to a female sealed inside hollow nest cavity, Tangkoko Dua Saudara Nature Reserve, Sulawesi, Indonesia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male delivering figs to female sealed inside hollow tree, Tangkoko-Dua Saudara Reserve, Indonesia

Mark Jones / Sulawesi Red-knobbed Hornbill (Aceros cassidix) breeding male in a fruiting Fig tree (Ficus forsteni) 32 meters above the ground in rainforest canopy, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, In...

Mark Jones / Sulawesi Red-knobbed Hornbill (Aceros cassidix) breeding male in fruiting Fig (Ficus forsteni), Tangkoko-Dua Saudara Nature Reserve, Sulawesi, Indonesia

Fred Bavendam / Paper Nautilus (Argonauta nodosa) is actually a pelagic Octopus, females make the parchment-like shell to carry incubating eggs, South Australia

Ann & Steve Toon / Red knobbed coot (Fulica cristata) on water, Intaka Island, Cape Town, South Africa, February

Pete Oxford / Yellow knobbed Curassow (Crax daubentoni) Medellin Zoo, Medellin, Antioquia Province, Columbia, South America, captive

Edwin Giesbers / Male Sulawesi red-knobbed hornbill (Aceros cassidix) portrait, captive

Edwin Giesbers / Sulawesi red-knobbed hornbill (Aceros cassidix) pair, portraits, captive

Edwin Giesbers / Sulawesi red-knobbed hornbill (Aceros cassidix) pair, portraits, captive

Edwin Giesbers / Male Sulawesi red-knobbed hornbill (Aceros cassidix) head portrait, captive

Edwin Giesbers / Male Sulawesi red-knobbed hornbill (Aceros cassidix) head portrait, captive

Brent Stephenson / Red-knobbed Imperial Pigeon (Ducula rubricera) perched on a mossy branch. Captive. Kavieng, New Ireland, New Guinea, April.

Wild Wonders of Europe / Oxford / Red-knobbed / Crested coot (Fulica cristata) captive, Cañada de los Pájaros Reserve where they have a breeding program, Huelva Province, Andalusia, Spain, May 2009

Wild Wonders of Europe / Oxford / Red-knobbed / Crested coot (Fulica cristata) on water, Captive, Cañada de los Pájaros Reserve where they have a breeding program, Huelva Province, Andalusia, Spain, May 2009

Konrad Wothe / Red-knobbed Sea Star (Protoreaster linckii) pair in shallow water, Zanzibar, Tanzania

Tim Laman / Male Knobbed hornbill (Aceros cassidix) with fruit of wild fig (Ficus sp) Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Male Knobbed hornbill (Aceros cassidix) flying from nest. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) at nest hole. Chick is near fledging and female has emerged to assist male in feeding chick. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island,...

Tim Laman / Knobbed hornbill (Aceros cassidix) male (right) and female perched in tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Knobbed hornbill (Aceros cassidix) fledgling chick just after fledging. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Knobbed hornbill (Aceros cassidix) fledgling chick on the ground after emerging from nest (perhaps too early to fly?) Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Male Knobbed hornbill (Aceros cassidix) at nest hole. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Knobbed hornbill (Aceros cassidix) male (left) and female (right) perched in tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) at nest holding fruit in bill. Strangler fig tree growing on the nest tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed Hornbill (Aceros cassidix) perched. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) outside nest. Chick in nest is near fledging and female has emerged to assist male in feeding chick. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi...

Tim Laman / Knobbed hornbill (Aceros cassidix) chick peering out from the nest hole, Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) feeding chick in nest. Chick is near fledging and female has emerged to assist male in feeding chick. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawes...

Tim Laman / Female Knobbed hornbill (Aceros cassidix) calling in tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Male Knobbed hornbill (Aceros cassidix) flying to nest, Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Male Knobbed hornbill (Aceros cassidix) with fruit of wild fig (Ficus) Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) female at nest. Chick is near fledging and female has emerged to assist male in feeding chick. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Islan...

Tim Laman / Female Knobbed hornbill (Aceros cassidix) preening in tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Knobbed Hornbill (Aceros cassidix) chick peering out from nest hole. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) perched in tree. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Female Knobbed hornbill (Aceros cassidix) at nest hole. Chick in nest is near fledging and female has emerged to assist male in feeding chick. Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi...

Bruno D'Amicis / Red-knobbed coot (Fulica cristata) adult among reeds, Northern Morocco, NW Africa

Bruno D'Amicis / Red-knobbed coot (Fulica cristata) adult among reeds, Northern Morocco, NW Africa

Thomas Marent / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male bringing food to female at nest, Tangkoko Nature Reserve, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} pair flying, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male flying from nesthole, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} chick peering out of nesthole, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male with insect prey, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} Male (left) and female (right) Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male flying, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} female at nesthole with fruit in beak, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male with fruit in beak, Sulawesi, Indonesia

Nature Production / Sulawesi red nosed / knobbed hornbill {Aceros cassidix} male with fruit in beak, Sulawesi, Indonesia

JIM CLARE / Male Red knobbed hornbill with full crop at nest hole{Aceros corrugatus} Sulawesi, Indonesia

Richard Du Toit / Red knobbed coot {Fulica cristata} feeding chicks, Johannesburg, South Africa

Jose B. Ruiz / Portrait of Red knobbed / Crested coot (Fulica cristata) in water, Alicante, Spain

Richard Du Toit / Red knobbed coot at nest on lake {Fulica cristata} Gauteng, South Africa

Solvin Zankl / Sulawesi red-knobbed hornbill {Aceros / Rhyticeros cassidix} Sulawesi, Indonesia

Michael & Patricia Fogden / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male, Tangkoko Reserve, Sulawesi, Indonesia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male in a fruiting fig (Ficus forsteni) tree, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, Indonesia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) female before sealing herself inside nest cavity for four months, Tangkoko-Dua Saudara Nature Reserve, Indonesia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) breeding male in a fruiting Fig (Ficus forsteni) tree, 32 meters above the ground in rainforest canopy, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, I...

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male delivering figs to female sealed inside hollow tree, Tangkoko-Dua Saudara Reserve, Sulawesi, Indonesia

Fred Bavendam / Paper Nautilus (Argonauta nodosa) is actually a pelagic Octopus, females make the parchment-like shell to carry incubating eggs, South Australia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male delivering Figs to female sealed in hollow tree nest cavity, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, Indonesia

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) male delivering Figs to female sealed in hollow tree nest cavity, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, Indonesia

Solvin Zankl / close up of eye, Sulawesi red-knobbed hornbill {Aceros / Rhyticeros cassidix} Sulawesi,

Dave Watts / Red knobbed coot on nest {Fulica cristata} Spain

David Shale / Sulawesi red-knobbed hornbill (Aceros cassidix), captive.