Exotic species = Hobo Spiders. Blah!! Maybe it's been six years now, but still. Creepy.

I can't think of any wild species which were not here 500 years ago except maybe feral "domestic" cats, wild horses, and that herd of cattle I just read about. And I have to gather this info from my knowledge of the entire west, by the way, not just Montana.

oops. not sure.
some exotic fish entered river and lake .
being dumped there.kills of native species.

Here in Los Angeles, a new exotic species is the brown widow spider, Latrodectus geometricus. It was found about 3.5 years ago.

Wild turkey, eucalyptus trees and scotch broom. In the last five years I do not know of any new exotics.

Here in Connecticut, many foreign plants have become naturalized, included trees such as the Norway Pine. It's hard to place a date on the arrival of the coyote which is no longer rare. One recent arrival in the wild is the West Nile Virus. Is a virus consdered a specie? Bears all but disappeared, but are making a comeback. Ditto wild turkeys. Wild salmon disappeared and has not been brought back (yet?) despite major investment.

Most modern songbirds did not exist here until the pioneers moved across the plains, including the Eastern Kingbird. The elk have moved off the plains and into the mountains due to pressure from land development, including farming. Certain species of wild fish were introduced here, such as lake trout, and have caused serious harm to the native species. Exotic species that have appeared here are mostly domestics, such as emus, llamas and vicunas.

Walleye (fish) were transplanted; Squirrels were transplanted; bison (formerly a plains animal). The only exotic species that has appeared here in the last five (5) years would be an elephant (at the zoo.)

Periwinkle sure wasn't here, but today it does a damn good job covering front areas without being eaten by deer or destroyed by the red dirt.

Three wild species that were not found here 500 years ago: English sparrows, Amazonian parrots, Mediterranean fruitfly.

One exotic species that has appeared in the last 5 years: ludwigia

Japanese Knotweed

Once you start looking for it, it's *everywhere*. It sprouts back up from tiny root fragments, it absorbs huge amounts of water, it drowns out any other species around, and it's almost impossible to get rid of.

The only upside: The shoots are edible.

I'm realizing an even better question would be: Name a wild species that was not here 50 years ago. Or 5 years ago?

Google "invasive species" (or plants) and your state name.
Also the Extension office for your state.

Africanized bees, Argenitne black ants, Mediterannian fruit fles, sharpshooters, - lots of fruit pests- have appeared in my .lifetime.

The black ants have appeared withing the last 5 years.

1. Look around
2. Ask elderly neighbours
3. Ask the museum
4.Read up in the library
5. Think of any number of local urban animals and farm animals

Don't know, really, about the extinct ones. Not fair as a question, that's a true botany question. Although I can tell you kudzu shouldn't be here and is.