Officials in Christchurch, New Zealand have gotten such a good response to warning about Argentine ants (Linepithema humile), they're a bit overwhelmed. The majority of the calls have led investigators to relatively harmless native species. Scoop is reporting that, in an attempt to reduce the number of false alarms, they have empowered residents with an identification test: squash an ant or two and sniff the air. The native Darwin's ants (Doleromyrma darwiana) give off a pungent odor, while Argentine ants are unscented. Somehow I can't see them doing the same type of kill test to say, identify invasive birds or other charismatic megafauna.
Thanks to Val C. for sending in the link to this story.