Guy Edwardes / Portland Bill Lighthouse, Isle of Portland, Dorset, England, UK. November 2011.

Guy Edwardes / Portland Bill Lighthouse at night, Isle of Portland, Dorset, England, UK. September 2016.

Guy Edwardes / Portland Bill Lighthouse at sunset, Isle of Portland, Dorset, England, UK. November 2009.

Ingo Arndt / Brown Booby (Sula leucogaster plotus) head portrait, with wide bill open, Christmas Island, Indian Ocean, Australian Territory, November

Danny Green / Atlantic Puffins (Fratercula arctica) bill rubbing, Skomer Island, Wales, UK, April

Danny Green / Atlantic Puffin (Fratercula arctica) pair bill rubbing part of courtship ritual, Skomer Island, Wales, UK, May

Andres M. Dominguez / Dove's-foot crane's-bill leaf (Geranium molle) and algae in ice with air bubbles, Sierra de Grazalema Natural Park, southern Spain, February.

Markus Varesvuo / Puffins (Fratercula arctica) 'bill-knocking' in a display of courtship behaviour, Norway, Scandinavia, April.

Michael Pitts / Diver Ron Howse ascending the shot line in Lyme Bay, off Portland Bill, Dorset, England, UK, September 2010. Model released.

D. Parer & E. Parer-Cook / Platypus (Ornithorhynchus anatinus) grinding prey between plates of its bill, Atherton Tableland, Queensland, Australia

David Tipling / Huli Wigmen from the Tari Valley in Southern Highlands of Papua New Guinea, wearing a bill from Blyth's Hornbill as decoration, August 2011

Bence Mate / Close up of Grey Heron (Ardea cinerea) with bighead carp (Hypophthalmichthys nobilis) in bill, Lake Csaj, Kiskunsagi National Park, Hungary