Long enough for ecosystems to change, adapt and form as well as for animals to evolve based on their new environment. Considering that there are already rats & cockroaches adapting to pesticides, both birds & pests are most certainly adapting to cats to some degree after the passage of thousands of years.
Obviously there may be a point in restricting cats in more insular habitats such as small islands, but for anybody on a major continent it is rather pointless. Furthermore, cats serve an important purpose in hunting pests that spread alongside humans, primarily rats and mice, both of which can have an even more disastrous effect on local ecosystems.
Long enough for ecosystems to change, adapt and form as well as for animals to evolve based on their new environment. Considering that there are already rats & cockroaches adapting to pesticides, both birds & pests are most certainly adapting to cats to some degree after the passage of thousands of years.
Obviously there may be a point in restricting cats in more insular habitats such as small islands, but for anybody on a major continent it is rather pointless. Furthermore, cats serve an important purpose in hunting pests that spread alongside humans, primarily rats and mice, both of which can have an even more disastrous effect on local ecosystems.
https://www.science.org/doi/10.1126/science.aam8327