As a result of their relatively wide range of habitat types, the two woods support a wide range of wildlife.

INVERTEBRATES
A wide variety of invertebrates have been recorded, some of which are uncommon or otherwise unknown in the Rotherham area. Over 63 butterflies and moths have been found in Treeton Wood alone, these including Purple Hairstreak, Holly Blue and Comma. Other invertebrates found at the two sites include slugs and snails, earthworms, millipedes and centipedes, crustaceans, woodlice, spiders, earwigs, bugs, dragonflies, lacewings, beetles and flies.

Treeton Marsh is particularly rich in invertebrates including caddisflies and water beetles.

AMPHIBIANS, REPTILES & FISH
A variety of amphibians, fish and reptiles have been recorded from Treeton Marsh including Smooth Newt, Common Frog, Grass Snake and Three-spined and Ten-spined Sticklebacks.

This old, overgrown hedge on the southern edge of Hail Mary Hill Wood supports a wide variety of wildlife.

BIRDS
Birds recorded in Hail Mary Hill and Falconer Woods reflect the mix of habitats on the site. Birds preferring areas of more mature woodland, often with standing deadwood, include Great-spotted Woodpecker, Blackcap, Sparrowhawk and Tawny Owl. Wren and the summer vistors Chiffchaff and Lesser Whitethroat prefer woodland edges and clearings such as those associated with the power lines. Willow Tit, Reed Warbler and Willow Warbler are associated with marsh and streamside areas. The more open areas are also important, for example for displaying Woodcock and feeding Jays.

For a number of reasons, the bird fauna of Treeton Wood is less diverse than that of its neighbour. Treeton Wood lacks the relatively wet conditions found in parts of Hail Mary Hill Wood. The shrub layer is generally under-developed and there is also a shortage of mature trees for hole-nesting birds, as well as extensive areas of Birch, a tree little used by breeding birds. Despite this, Treeton Wood does contain a number of birds not already listed above. These include Green Woodpecker, Redpoll, Whitethroat, Tree Pipit, Treecreeper, Yellowhammer, Mistle Thrush, Long-tailed Tit, Song Thrush and Spotted Flycatcher. The last two of these are of particular importance as they are relatively infrequent and decreasing in numbers.

MAMMALS
A good variety of mammals has been recorded in Hail Mary Hill and Falconer Woods, including Fox, Pigmy Shrew, Field Vole, Bank Vole, Brown Hare and Weasel. Harvest Mouse, Water Vole and Water Shrew have been recorded from the marshland area. The site is also used as a feeding area by Noctule and Pipistrelle Bats but although a number of suitable trees are present, no bat roosts have ever been found.