Shattil & Rozinski / Pair of Plain Chachalaca singing {Ortalis vetula} Texas, USA

John Cancalosi / North american pika {Ochotona princeps} territorial display, Colorado, USA

Tom Vezo / Californian sealion {Zalophus californianus} pup roaring, Galapagos

DAVID TIPLING / Black mantled howler monkey {Alouatta palliata} male howling from treetop, Soberiana NP, Panama.

DAVID TIPLING / Black mantled howler monkey {Alouatta palliata} male howling on branch, Soberiana NP, Panama.

Bernard Castelein / Black-headed gull calling (Chroicocephalus ridibundus) Belgium

DAVID TIPLING / Common crane calling {Grus grus} Hornborga, Sweden

Tom Vezo / Red winged blackbird male singing {Agelaius phoeniceus} Tucson, Arizona, USA

Mike Read / Buff-streaked chat {Oenanthe bifasciata} male perched on rock, singing, Wakkestroom, South Africa, November

Mike Read / Buff-streaked chat {Oenanthe bifasciata} male perched on rock, singing, Wakkestroom, South Africa, November

Tom Vezo / Red winged blackbird male singing {Agelaius phoeniceus} Tucson Arizona USA

Yves Lanceau / Brahma Hen, blue, cock crowing, studio portrait