Magnus Lundgren / Wild Wonders of China / Sea apple, eating, using arm to transfer food into mouth. Ninepin Group or Kwo Chau Islands, Sai Kung District of Hong Kong, China

Marie Read / Northern harrier (Circus cyaneus) pair exchanging food in courtship while flying near nest, Montezuma National Wildlife Refuge, New York, USA.

Doug Wechsler / Two Ferruginous carpenter ants (Camponotus chromaiodes) on a Common jewelweed leaf (Impatiens capensis) sharing food with Aphids (Aphididae) they are tending, Bucks County, Pennsylvania, USA. Septembe...

Emanuele Biggi / Three Turtle-ant (Cephalotes sp.) engaged in grooming and anal-trophallaxis, Los Amigos Biological Station, Peru.

Ripan Biswas / Two Asian weaver ants (Oecophylla smaragdina) engaged in trophallaxis, social feeding, West Bengal, India.

Rose Summers / Three Common kestrel (Falco tinnunculus) chicks sitting at entrance of nest in tree trunk, male arrives with food and feeds chick before flying away, Devon, England, UK, June.

David Perpinan / Barn swallow (Hirundo rustica) fledgling perched on a cable recieves food from its parent, Cuenca, Spain, July.

David Perpinan / Two Barn swallow (Hirundo rustica) fledglings perched on a cable, parent flies in and gives one chick food, Cuenca, Spain, August.

David Perpinan / Two Barn swallow (Hirundo rustica) fledglings perched on a cable, parent flies in and gives one chick food, Cuenca, Spain, August.

David Perpinan / Two Barn swallow (Hirundo rustica) fledglings perched on a cable, parent flies in and feeds one chick while the other chick stretches its wings, Cuenca, Spain, August.

David Perpinan / Barn swallow (Hirundo rustica) fledglings perched on a cable, parent flies in and feeds one chick, Cuenca, Spain, August.

David Perpinan / Barn swallow (Hirundo rustica) feeding chick, Barcelona, Spain, June.