Timber Wolf Cub, Canis Lupus #1
M. Watson
Common Yellowthroat
Steve and Dave Maslowski
Houston Toad
Dante Fenolio
Golden-crowned Sparrow Singing
Paul J. Fusco
Marsh Wren
Richard Hansen
Tungara Frog Vocalizing #1
Gregory G. Dimijian, M.D.
Golden Eagle #1
Jean-Louis Klein & Marie-Luce Hubert
Siberian Husky Howling
Jean-Michel Labat
Tree Swallows Singing
Anthony Mercieca
Four Choir Boys Singing, C.1950-60s
H. Armstrong Roberts/ClassicStock
Mccowns Longspur #1
James Zipp
Winter Wren #2
James Zipp
Acorn Woodpecker #1
Anthony Mercieca
Chimpanzee #2
Mark Newman
Green Treefrog Vocalizing
Dante Fenolio
Tungara Frog Vocalizing
Gregory G. Dimijian, M.D.
Northern Fur Seal Vocalizing
Mark Newman
Harp Seal Pagophilus Groenlandicus #2
Gerard Lacz
Zebra Finch Taeniopygia Guttata
Gerard Lacz
Southern Skuas
Jean-Louis Klein & Marie-Luce Hubert
Domestic Chicken Crowing
Gary K. Smith/FLPA
American Alligator Alligator #1
John Serrao
Salmon-crested Or Moluccan Cockatoo #2
Gerard Lacz
Samoyed at Sunset
Kent Dannen and Photo Researchers
Northern Fur Seal
Art Wolfe
Mallard Drake Quacking
Anthony Mercieca
Brown Basilisk Lizard
Gerard Lacz
Pine Woods Treefrog
John Serrao
Green-eared Barbet Megalaima Faiostricta
Bob Kennett
Prairie Warbler, Dendroica Discolor
James Zipp
Field Sparrow #1
James Zipp
South African Fur Seal A. Pusillus
Gerard Lacz
Common Yellowthroat, Geothlypis Trichas
James Zipp
Rock Wren, Salpinctes Obsoletus #1
James Zipp
Spotted Towhee, Pipilo Maculatus
James Zipp
Song Sparrow, Melospiza Melodia
James Zipp
Worm-eating Warbler
Jim Zipp
Brandts Cormorant Calling
Anthony Mercieca
Amazon Milk Frog #5
Gerard Lacz
Harp Seal Pagophilus Groenlandicus
Gerard Lacz
Manul Or Pallass Cat Otocolobus Manul #4
Gerard Lacz
Hooded Seal Cystophora Cristata #1
Gerard Lacz
Chimpanzee Pan Troglodytes #12
Gerard Lacz
Santa Cecilia Cochran Frog
Francesco Tomasinelli
Red-legged Honeycreeper
James Zipp
Horned Lark, Eremophila Alpestris
James Zipp
Jersey Cow Communicating
Inga Spence
Village Weaver Ploceus Cucullatus #1
Gerard Lacz
Peregrine Falcon Falco Peregrinus
Gerard Lacz
Green-eared Barbet Megalaima Faiostricta
Robert Kennett
Great Horned Owl, Bubo Virginianus #3
James Zipp
Blue-winged Warbler
Jim Zipp
Peregrine Falcon In Flight #1
Anthony Mercieca
Peregrine Falcon Falco Peregrinus #1
Gerard Lacz
Male Lazuli Bunting Singing
Thomas And Pat Leeson
Northern Waterthrush, Parkesia
James Zipp
Yellow Warbler, Dendroica Petechia #1
James Zipp
Wood Duck Male Calling
Anthony Mercieca
Chick Calling Out
Gerard Lacz
Chimpanzee Pan Troglodytes #1
Gerard Lacz
Harlequin Poodle Puppy #3
Johan De Meester
North American Grey Wolf
Gerard Lacz
Chilean Four-eyed Frog
Danté Fenolio
Common Buzzard #2
Dr. Rainer Herzog
Western Meadowlark
James Zipp
Winter Wren #1
James Zipp