[The_Victor]

You may be an extensive reader but, apparently your perceptions of the value of a natural system is flawed. Most native species have a function wether perceived or unperceived. The introduction of a non-native serves merely to destroy balance. Although the balance of natural systems have already been radically altered, they do not need any additional help from people who refuse to keep their pets under control.

1m years ago finches didn't exist on the Galapagos Islands. At some point the "non-native" species was introduced, not by man I might add. At what point does a non-native species become native?

[Slings and Arrows]

At what point does a non-native species become native?

When a "Guest Worker" bill passes.

[Plateau]

Please refer to post 160. House cats will never be native, they are considered a domesticated species.

[Hound of the Baskervilles]

"At what point does a non-native species become native?"

Not at the point when it is on my property. Why should pet cats be allowed to wander on to my property?