Can cat urine damage car paint?

Yes, cat and dog urine contains urinary acids which will damage paint. On modern water based paints, the damage can be quite severe if the urine is not washed off quickly. The same goes for bird droppings, which should not be 'scrubbed off' as it contains grit particles which can scratch the paint. Soak bird droppings with fresh water, and when softened, rinse off with more clean water.

As with any foreign substance, a good coat of quality car wax will provide a barrier between the paint and contaminants.