Richard Du Toit / Burchell's Zebra (Equus burchellii) trio nuzzling, Itala Game Reserve, South Africa

Scott Leslie / Black-and-white Warbler (Mniotilta varia) male calling in spring, Maine

Alan Murphy/ BIA / Great Kiskadee (Pitangus sulphuratus) and Green Jay (Cyanocorax yncas) fighting, Texas

Donald M. Jones / Elk (Cervus elaphus) bull bugling, western Canada

Donald M. Jones / Curve-billed Thrasher (Toxostoma curvirostre) feeding on cactus flower nectar, southern Arizona. Sequence 2 of 2

Donald M. Jones / Cactus Wren (Campylorhynchus brunneicapillus) calling, southwestern Arizona

Donald M. Jones / Cactus Wren (Campylorhynchus brunneicapillus) pair with one calling, southwestern Arizona

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) in defensive posture, Espanola Island, Galapagos Islands, Ecuador

Alan Murphy/ BIA / Eastern Meadowlark (Sturnella magna) male calling, Texas

Mario Suarez Porras/ BIA / Grasshopper Warbler (Locustella naevia) calling, Asturias, Spain

Tui De Roy / Magellanic Penguin (Spheniscus magellanicus) pair calling near chicks, Saunders Island, Falkland Islands

Agustin Esmoris / Southern Elephant Seal (Mirounga leonina) male calling and bleeding after fight, Puerto Madryn, Argentina