The American Veterinary Medical Association said symptoms to watch for include a staggering gait, the inability to retract claws, extreme sensitivity to touch, tremors, and seizures. The illness usually lasts for a few days to a few weeks, but can also linger for more than a year.
It’s not an either/or thing. Outdoor cats are causing an ecological disaster when it comes to birds. The big solution is to spay and neuter as many as possible, especially pets. Even indoor ones can escape.
https://en.wikipedia.org/wiki/Cat_predation_on_wildlife