Chase Dekker / Lesser Flamingo (Phoenicopterus minor) pair fighting, Amboseli National Park, Kenya

Martin Willis / Victoria's Riflebird (Ptiloris victoriae) male in courtship display, Atherton Tableland, Queensland, Australia. Sequence 2 of 3

Suzi Eszterhas / Leopard (Panthera pardus) six-week-old cub nuzzling mother, Jao Reserve, Botswana

Winfried Wisniewski / African Lion (Panthera leo) males nuzzling, Masai Mara, Kenya

Donald M. Jones / Yellow-headed Blackbird (Xanthocephalus xanthocephalus) male calling, Montana

Donald M. Jones / Western Meadowlark (Sturnella neglecta) male calling, Montana

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

Donald M. Jones / Black-tailed Prairie Dog (Cynomys ludovicianus) pair greeting, South Dakota

Tomasz Zawadzki/ BIA / Blue-headed Wagtail (Motacilla flava) calling, Poland

Tomasz Zawadzki/ BIA / Great Reed-Warbler (Acrocephalus arundinaceus) calling, Poland

Glenn Bartley/ BIA / Chestnut-bellied Cuckoo (Hyetornis pluvialis) calling, Jamaica

Glenn Bartley/ BIA / Patagonian Sierra-Finch (Phrygilus patagonicus) male calling, Andes, Chile