Marie Read / Black skimmers (Rynchops niger), three in non-breeding plumage on beach, Fort De Soto Park, St. Petersburg, Florida, USA. January. Digitally altered to remove distractions.

Guy Edwardes / Saddle-billed stork (Ephippiorhynchus senegalensis), Moremi Game Reserve, Botswana.

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills whilst feeding, Lake Kerkini, Greece, February.

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills whilst feeding, Lake Kerkini, Greece, February.

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills whilst feeding, Lake Kerkini, Greece, February.

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills whilst feeding, Lake Kerkini, Greece, February.

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills whilst feeding, Lake Kerkini, Greece, February. Highly commended in World of Birds category in the Cadiz Photo Nature Competi...

Marie Read / Royal terns (Sterna maxima) pair crossing bills during courtship behaviour, Fort DeSoto Park, Florida, USA

Laurent Geslin / Female blackbird (Turdus merula) catching worms on an urban lawn in London, UK

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

Bence Mate / Dalmatian pelicans (Pelecanus crispus) low angle perspective of open bills, Lake Kerkini, Greece, February. Highly Commended, 2011 Wildlife Photographer of the Year competition.

Pete Oxford / Finch specimens at the Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, L to R Top: Large Ground Finch (Geospiza magnirostris), Woodpecker Finch (Cactospiza pallidu...

Wild Wonders of Europe / Peltomäki / Dalmatian pelican (Pelecanus crispus) with beak wide open, Lake Kerkini, Macedonia, Greece, February 2009

Edwin Giesbers / Toco toucan (Ramphastos toco), close-up of face, Costa rica

Yva Momatiuk & John Eastcott / King Penguin (Aptenodytes patagonicus) group walking, pointing long bills on gravel beach, fall, Gold Harbour, South Georgia, Southern Ocean, Antarctic Convergence

Staffan Widstrand / Australian pelicans on beach {Pelecanus conspicillatus} Queensland, Australia

Staffan Widstrand / Australian pelicans {Pelecanus conspicillatus} Queensland, Australia

Ashish & Shanthi Chandola / Malabar pied hornbill (Anthracoceros coronatus), male perched in tree. Dandeli Wildlife Sanctuary, Karnataka, India.

Sandesh Kadur / Pair of Waved albatrosses (Phoebastria irrorata) displaying, tapping beaks, Galapagos Islands, Ecuador.

Loic Poidevin / Black-tailed godwit (Limosa limosa). Vendeen marsh, Vendee, Pays-de-la-Loire, France. April.

Nick Upton / Pair of Avocets (Recurvirostra avosetta) foraging in a shallow lake, sweeping their bills through the water to filter feed, with a Black-headed gull (Chroicocephalus ridibundus) landing on a small isl...

Julian Hume / Illustration of extinct Kaua'i mole ducks (Talpanas lippa) forage on the forest floor for invertebrate prey with their broad, sensitive bills.

Marie Read / American avocet (Recurvirostra americana) pair performing post-copulatory display (as copulation ends, the male slides off the female leaving his wings draped over her and crossing his bill with hers,...

Marie Read / American Avocet (Recurvirostra americana), pair copulating, Bear River Migratory Bird Refuge, Utah, USA, May.

Danny Green / Atlantic Puffin (Fratercula arctica) courtship display, rubbing bills, Skomer Island, Wales, UK, May

Brent Stephenson / Australasian gannet (Morus serrator) crossing bills as they display to each other at their nest site, Cape Kidnappers, Hawkes Bay, New Zealand, November.

Brent Stephenson / Australasian gannet (Morus serrator) pair crossing bills as they display to each other at their nest site, Cape Kidnappers, Hawkes Bay, New Zealand, November.

Marie Read / Horned puffins (Fratercula corniculata) pair interacting by touching bills while perched on cliff ledge, St. Paul Island, Pribilofs, Alaska, USA, July.

Rolf Nussbaumer / Sword-billed Hummingbird (Ensifera ensifera) male feeding from passionflower (Passiflora mixta), Papallacta, Ecuador, Andes, South America. January.

Brent Stephenson / Adult Black-billed gulls (Larus bulleri) with bills open, calling noisely whilst displaying at the breeding colony. Miranda, Auckland, New Zealand, October. Endangered species.

Brent Stephenson / Pair of Australasian gannets (Morus serrator) crossing bills during courtship display. Cape Kidnappers, Hawkes Bay, New Zealand, November.

David Tipling / Carved ivory of a Helmeted Hornbill (Rhinoplax vigil).

LYNN M. STONE / Royal Terns (Thalasseus maximus) in foreground with Caspian Tern (Sterna caspia) pair in background, note much more slender, more orange bills of Royal Terns, in breeding plumage, on shoreline of Tamp...

Laurent Geslin / Female blackbird (Turdus merula) catching worms on an urban lawn in London, UK

David Tipling / Huli Wigmen with Blyth's Hornbill bills as necklace decoration, Tari Southern Highlands, Papua New Guinea, August 2011

Tui De Roy / Sword billed hummingbird (Ensifera ensifera) showing how it uses its long beak to feed on specific flowers, Yanacocha Reserve, Jocotoco Foundation, 3,200m altitude on west slope of Pichincha Volcano,...

Tui De Roy / Sword billed hummingbird (Ensifera ensifera) profile showing beak is longer than body, Yanacocha Reserve, Jocotoco Foundation, 3,200m altitude on west slope of Pichincha Volcano, Andean cloud forest,...

Tui De Roy / Sword billed hummingbird (Ensifera ensifera) profile in flight, Yanacocha Reserve, Jocotoco Foundation, 3,200m altitude on west slope of Pichincha Volcano, Andean cloud forest, Ecuador

Roland Seitre / Platypus (Ornithorhynchus anatinus) underwater. Captive. Australian Reptile Park, Gosford, New South Wales.

Roland Seitre / Platypus (Ornithorhynchus anatinus) bill with a crayfish. Crayfish. Australian Reptile Park, Gosford, New South Wales.

Roland Seitre / Sword-billed Hummingbird (Ensifera ensifera) in flight. Guango lodge, Cuyuja, Napo, Ecuador.

Sandesh Kadur / Malabar Pied hornbill (Anthracoceros coronatus) feeding in tree, Western Ghats, Southern India

Dr. Axel Gebauer / Girl wearing a hat with a hornbill lower mandibel, a raptor feather and civet fur, Tawang, Arunachal Pradesh, India 2008

Peter Cairns / 2020VISION / Prints of waders in mudflats and holes where bills have probed, Morecambe Bay, Cumbria, England, UK, February

Andrew Parkinson / 2020VISION / A pair of Mallards (Anas platyrhynchos) touching bills in the snow on a frozen lake, Derbyshire, England, UK, January

Brent Stephenson / Two Gentoo Penguins (Pygoscelis papua) jab at each other with open bills. Mikkelsen Harbour, Antarctic Peninsula, Antarctica, December.

Brent Stephenson / Pair of Australasian Gannets (Morus serrator) rubbing their bills together in a greeting display at the nest. Muriwai, Auckland, New Zealand, November.

Brent Stephenson / Pair of Australasian Gannets (Morus serrator) rubbing their bills together in a greeting display. Cape Kidnappers, Hawkes Bay, New Zealand, September.

Edwin Giesbers / Shoebill / Whale headed stork (Balaeniceps rex) head portrait, captive

Edwin Giesbers / Shoebill / Whale headed stork (Balaeniceps rex) portrait, captive

Edwin Giesbers / Shoebill / Whale headed stork (Balaeniceps rex) head portrait, captive

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

LYNN M. STONE / Portrait of White ibis (Eudocimus albus) St. Petersburg, Florida, USA, June

LYNN M. STONE / American White pelican (Pelecanus erythrorhynchos), adult in breeding plumage (note hard knob on upper mandible, a characteristic feature of white pelicans only in the courtship and early breeding sea...

Andrew Parkinson / Puffin (Fratercula arctica) looking above grass bank. Skomer Island, Wales, UK, May.

Stefan Huwiler / Toco Toucan (Ramphastos toco) feeding on mango. Pantanal, Brazil, South America.

Stefan Huwiler / Toco Toucan (Ramphastos toco) adult in mango tree. Pantanal, Brazil, South America.

Charlie Summers / Pair of Wandering Albatross (Diomedea exulans) clicking bills together in courtship behaviour, at nest site, Pryon Island, South Georgia.

Charlie Summers / Pair of Wandering Albatross (Diomedea exulans) clicking bills together in courtship behaviour, at nest site, Pryon Island, South Georgia.

Andrew Walmsley / Shoebill / Whale headed stork (Balaeniceps rex) captive, Singapore Zoo

Pete Oxford / Two Pale-mandibled Aracaris (Pteroglossus erythropygius) captive. Ecuador, South America

Anup Shah / Head portrait of female Saddle-bill stork(Ephippiorhynchus senegalensis) Masai Mara National Reserve, Kenya. February

Hanne & Jens Eriksen / Hall's giant petrel {Macronectes halli} close-up, Gold Harbour, South Georgia

Tim Laman / American White Pelican (Pelecanus erythrorhynchos) feeding in Mrazek Pond, Everglades National Park. Florida, USA.

Rolf Nussbaumer / Sword-billed Hummingbird (Ensifera ensifera) female feeding from Datura flower, Papallacta, Ecuador, Andes, South America, January

Edwin Giesbers / Keel billed Toucan (Ramphastos sulfuratus), close-up of face, Costa Rica

Edwin Giesbers / Keel billed Toucan {Ramphastos sulfuratus}, Costa Rica

Jouan & Rius / Australian / Indonesian white ibis (Threskiornis molucca), Queensland, Australia

Jouan Rius / Puffin (Fratercula arctica) having shed its bill plates at the end of the summer, Shetland Islands, Scotland, UK

Paul Hobson / Australian Pelican (Pelecanus conspicullatus), mass of beaks, Kangaroo Island, South Australia

Paul Hobson / Australian Pelican (Pelecanus conspicullatus) adult feeding with fish in bill, Kangaroo Island, South Australia

Rolf Nussbaumer / Roseate Spoonbill (Platalea ajaja) wading Welder Wildlife Refuge, Sinton, Texas, USA. June 2005

Rolf Nussbaumer / American Wood Ibis / Wood Stork (Mycteria americana) with beak open, Sanibel Island, Florida, USA. December 1998

Rolf Nussbaumer / Group of American White Pelicans (Pelecanus erythrorhynchos) with bills open, Rockport, Texas, USA. December 2003

Kerstin Hinze / Sanderling (Calidris alba) using bill to search for food in sand, Helgoland, North Sea, Germany

Kerstin Hinze / Great Frigate (Fregata minor) feeding chick on nest, Genovesa, Tower, Galapagos Islands, Ecuador

Kerstin Hinze / Keel-billed Toucan (Ramphastos sulfuratus) portrait, South America

Kerstin Hinze / Black-tailed Godwit (Limosa limosa) standing on one leg, Lake Neusiedl, Burgenland, Austria

Rolf Nussbaumer / Groove-billed Ani (Crotophaga sulcirostris) Lake Corpus Christi, Texas, USA. May 2003

Rolf Nussbaumer / Great Blue Heron (Ardea herodias) wading in pond with bill open, Starr County, Rio Grande Valley, Texas, USA. May 2002

Rolf Nussbaumer / Common Snipe (Gallinago gallinago) Willacy County, Rio Grande Valley, Texas, USA. March 2004

Tom Vezo / White ibis (Eudocimus albus) feeding in shallow water, Florida, USA

Hanne & Jens Eriksen / Common noddy {Anous stolidus} on rock with bill open, Daymaniyats, Oman

Staffan Widstrand / Australian pelican head portrait {Pelecanus conspicillatus} Queensland,

Yva Momatiuk & John Eastcott / Northern Gannet (Morus bassanus) pair fencing with their bills in greeting ritual, Bonaventure Island breeding colony, Quebec, Gaspesie Peninsula, Canada

Yva Momatiuk & John Eastcott / Northern Gannet (Morus bassanus) pair fencing with their bills in a greeting ritual, summer season, Newfoundland, Canada

Tom Vezo / Short billed dowitcher in water {Limnodromus griseus} Churchill, Canada.

Tim Laman / Rhinoceros hornbill (Buceros rhinoceros) female scratching bill against tree branch, Halabala Wildlife Sanctuary, Narathiwat Province, Thailand.

Jack Dykinga / Pair of Black-necked stilt (Himantopus mexicanus) in courtship ritual, touching bills. Gilbert Riparian Preserve, Arizona, USA. 5 of 5 in a series showing courtship and mating ritual.

Marie Read / Female Northern cardinal (Cardinalis cardinalis) with snow-covered bill from eating seeds in deep snow, winter, New York, USA.

Doug Gimesy / Two Black-browed albatross (Thalassarche melanophris) rub their bills together - part of a bonding ritual. West Point Island, The Falkland Islands.