There are substantial native mammal, reptile and bird populations found within the Hay Shire, with the Lower Murrumbidgee area home to thousands of species of native and introduced fauna that occupies a multitude of different environments.
Commonly found throughout the Shire are Red and Grey Kangaroo, Short-beaked Echidna, Galah, Cockatoo and Wedge-tail eagle. The Lower Murrumbidgee is home to a wide range of native and introduced aquatic fauna which inhabit wetlands, rivers and associated creek habitats. Some important species include the Green and Golden Bell frog, Freckled duck, Blue-bill duck, Black-tailed Godwit, Painted Honeyeater, Painted Snipe, Great Egret, Caspian Tern, Magpie Goose, Australian Bittern, Australian Bustard and Platypus.
Other common species include Black swan, Wood duck, Common bullfrog, Pelican, Murray Cod and the Water Rat with Carp the most common fish species along with Redfin Perch and Golden Perch.
The catchment is home to significant species of less common birds and mammals, including Plains Wanderer, Koala, Superb Parrot, Grey Falcon, Southern Bell Frog, Bilby, Brolga, Brush Thick-Knee, Greater Long-Eared Bat, Square-tailed Kite, Diamond Firetail, Grey Falcon, Pied Honeyeater, Grey-crowned Babbler, Tiger Quoll and there is an Ibis rookery west of Maude.
A number of these species are quite elusive and not readily observed throughout the whole Shire.