To Be or Not to Be: Introduced Species

I received a comment on my home page that prompted me to produce some thoughts on introduced species more thoroughly. Of course, I could dedicate many posts for this topic, analyzing each situation individually, but this summary will do for now.

Don't be fooled by this bird's innocent "walking the fence" look. He's picked sides. Yes, he's all for destroying agriculture and isn't ashamed of it.

First of all, there is a difference between and an "introduced" species and an "invasive" one. While nearly all invasives are introduced, not all introduced species are invasives. Take, for example, the starling. The starling is a little old-world bird that somehow made its way to North America as some European immigrant's idea of "a touch of home." So it is certainly an introduced species. But is it harmful, unwanted, that is, invasive? With astoundingly aggressive reproductive habits and a love for the farmer's crop, there is certainly a case to be made for that position. However, the starling has become largely stable in its new environment and, as far as I know, has not caused the extinction of any other animals (though it has contributed to the endangerment of a few warbler species--though habitat destruction is probably the primary concern for those species). So from an ecologists perspective, the starling is not particularly invasive.

The American kestrel might be the hero in the battle
against starlings.

However, a farmer will tell you quite a different story. The starling moves in massive flocks during migration and they often make purposeful stops at farmer Brown's fields. In a day, the giant flock can consume nearly everything the farm had to offer the world. So from an economical perspective, the starling is a terror. Though I may have exaggerated.
So, the question is, when do we act to remove a species and when should we simply allow things to follow a course unaltered by human intervention. Even if you don't believe that it is our God-given responsibility to care for creation, the moral obligation to do so in the case of introduced species is not diminished. It was people who introduced them in the first place (though not always purposefully) so they are clearly the peoples responsibility.
When it comes down to it, every situation must be taken on an individual basis. In the case of the starlings, they are, in every practical sense, here to stay. There is no eradicating them. So, I would say, just let them alone. However, that kind of thinking does not remove the economic problem. The reality is, the starlings cannot be removed entirely. Thus, some method of coexistence must be reached for both starlings and farmer's crops. Many solutions have been thought up to deal with this problem (nets, guns, pranks, etc.) but none are the cure-all (starlings are too smart). Perhaps the best suggestion is natural predators. As it turns out, the American kestrel, like its European relation, loves the taste of starling McNuggets. Unfortunately, because of pesticides and destruction of suitable habitat, the kestrel doesn't frequent farms. If more could be done to favour those birds, the starlings wouldn't do so well.

Many state parks put up educational signs informing the
public of the invasive species in the area to prevent spread.
This one is at Big Lagoon State Park in Florida where
exotics (tropical invasives) are a problem.

Then there is the question of killing. If you can be confident that a harmful animal will be exterminated, then go ahead and exterminate. Problems over.
However, sometimes, as in the case of the starling, you could shoot hundreds of the birds and there would still be thousands waiting to eat your crops. So, is life really worth so little that you would take it without any long-term solution? This, of course, is debatable. Killing some starlings can frighten many others away and might just be the ticket to saving your crop that year. I think in such a case it is okay to shoot some of the birds, though such a position is up for debate. Now, if it were a native bird devouring the crops, I would say killing should be out of the question. But, since it is an introduced species, we placed it there in the first place, so I suppose we can take it out. But this really is a difficult thing to give a definite answer for.
In the end, don't forget that you are responsible for the state of creation. Every human is. We have a soul and the ability to act outside of our natural bounds. So don't take invasive species lightly. Be sure to enjoy nature (don't let a starling in picture stress you out) and even enjoy the introduced species, but act when things get out of hand. Sometimes, when a very invasive species cannot be exterminated, keeping it at bay is the next best thing. If anyone has any questions about a particular introduced species just let me know. I'd be glad to answer any questions and let you know of some possible course of action for that particular species.