https://phys.org/news/2019-01-wildlife-vet.html

Most clinics only saw a handful of wildlife patients every week, with birds and marsupials such as possums the most common. Sadly, the majority (82%) of wildlife arrived in veterinary care due to trauma of some kind. The most common cause was animals being hit by cars, followed by undefined trauma and predation by another animal.

Most clinics examined and treated wildlife for free, with less than 10% receiving some kind of payment. These were usually made by wildlife rehabilitation groups or members of the public.