Owls are a common but often overlooked predator of small mammals in Australia. Though they don't exact the same toll as feral cats, they're expert hunters using sight and sound to locate their nocturnal prey.
A quirk of owl feeding behaviour is that they need to disgorge the indigestible components of their prey. These are produced as owl pellets, or as I like to call them, owl vomit. And they're really useful to us ecologists.
Owl pellets are packed full of information about the prey, in the form of skeletal remains, fur or feathers. These are readily identifiable and provide data about what species occur in the local area, and how the species present in the landscape change over time.