If every public-spirited citizen who has grieved over the almost total loss of song birds through the pugnacity of the sparrow would follow the example set by Jack Durney, a downtown youth, it would not be very long before the feathered songsters would return again in full force, says the Philadelphia Record. On the roof of a building in the back yard of the Durney homestead a sparrow trap is erected and is in full swing night and day. Not only are the feathered pests captured by the dozen, but all the friends of the Durney family for squares around will testify to the fact that nothing on earth compares with fat sparrows when cooked in a potpie. The trap is one into which the birds hop to get the grain and bread crumbs plainly in sight. Once inside the birds did not know enough to come out. The sparrows feed more on a cloudy and windy day than on a still, bright day, but no matter what the weather is, it is a poor day when the trap will not yield fifty sparrows. Mr. Durney says he is going to get his trap patented and then induce the legislature to pay so much apiece for dead sparrows. Then he’ll make his trap earn him a fortune.
“There’s good eatin’ on them ____” (fill in the blank yourself. I’m thinking of this)
Obviously, Mr. Durney’s apparatus wasn’t successful enough. For instance, see this density map from the USGS Bird ID Center. According to one site, English sparrows were introduced in Philadelphia in 1869, so it didn’t take long for them to take over the city.
The list of introduced species is longer than your arm, some which we don’t mind, usually, like lilacs, others which are well-known to be disruptive, like purple loose-strife, and still others which are new and scary, like the emerald ash borer.
It’s been said (by me in a paper that you’ll never get to read) that ecological succession is like a gigantic game of rock-paper-scissors. However, with introduced species, it’s less like the game played in the US and Japan — with three equally-dominant plays, and more like the German version. That has a fourth play (dwell, or hole) that can only be beat by paper, thereby changing the dynamics of the (eco)system. If you’ve seen kids play RPS, you know the weapons escalate until somebody calls “nuclear bomb.”
What a nasty thought. But where does it end? Do we introduce new species to eat the last “invasive” one? Are we like the old woman who swallowed a fly? What happens when we swallow the horse?
![swallowed a fly]("http://i.imdb.com/Photos/Ss/0082971/IJ1_IA_193_R.jpg"){kind=link}