Tuesday, June 12, 2007

"Exotic" Isn't Always a Good Thing.

The bird in the picture next to this post is a common myna (Acridotheres tristis), a native of southeastern Asia. The picture was taken by me on a Marine Biology field trip. Unfortunately, the trip wasn't to India, but to Florida--I snapped the picture in a Wal-Mart parking lot in Homestead. Florida cities have more birds than do many. Among the most common birds I saw were mynas, collared doves, rock pigeons, starlings, monk parakeets, cattle egrets, house sparrows, and house finches. If you know anything about birds, you know that not one of those species is native to Florida. In fact, Florida has had reports of nearly 200 species of exotic birds. Many of them are known only from a sighting or two, but others, including all of those listed above, have established breeding populations in Florida. Many of these birds are escaped pets--or worse, pets that have been released into the wild by owners tired of caring for them.

So what? Why should we care if a new bird or two is introduced into an area? Exotic birds compete with native birds for food and nesting space. For example, many authorities blame the decline in populations of native bluebirds on the fact that starlings and house sparrows outcompete them for the best nesting sites. Non-native birds may carry infections to which native birds lack any immunity. Non-native birds (such as parakeets and mynas) may act as agricultural pests. If they hybridize with native birds, non-native birds may dilute the gene pool of native birds.

The problem of introduced exotic species receives less attention than some other environmental maladies, but it has the potential to cause great harm to natural ecosystems, and to human activities. Everyone has heard stories of the problems caused by zebra mussels, fire ants, tiger mosquitoes, and killer bees; stories of more bizarre exotics (such as monitor lizards, pythons, and monkeys) are less well known. Despite this, people still seem to ignore the exotic pet trade. Apparently folks in Louisiana are all excited about the possibility of selling red-eared sliders as pets, even though there is the possibility of the turtles carrying salmonella, the turtles don't live very long in captivity (they have the potential to live 40 years in the wild), and no one has determined just what increased pet trade will do to the wild populations. No one seems to be worried about the effects released turtles might have in areas outside their natural range.

Here's the deal: We already have dogs and cats, and they do enough damage to the environment. There is absolutely no need for people to have more exotic pets. This isn't about the "rights" of pet owners--you DO NOT have the right to put your local ecosystem at risk. If you need a pet, shelters are full of cats and dogs that need you, too. Do everyone a favor--pass on the baby alligator. Skip the boa constrictor. Leave the parrots where they belong.


Catnapping said...

We're suffering that problem right here in western Montana. Starlings crowding out our bluebirds.

Many of us have taken to putting out birdhouses with openings too small for starlings...I even have a few around the yard (where I used to live) so that the nuthatches and finches can nest without intrusion.

I hear teachers are starting to make this a yearly class project to help protect our smaller indigenous birds.

Keifus said...

Interesting...I would have gone with, "You don't have the right to put my ecosystem at risk, motherfucker."

I imagine the sorts that release their snakes and monkeys into the Florida swamps, are the same assholes that disclaim responsibility for their vicious or starving, barking dogs. (But my cat still craps outside...)

Everybody cares about bluebirds. Back in the DC burbs, there are zillions of little bluebird shelters; back at home, my mom has a habit of going all payback on the starlings. Any ugly, unloved species we should regret?


Archaeopteryx said...

My understanding is that most bluebirds are making a nice comeback specifically because of the attention they're getting, and the bluebird houses that people are putting up.

K--you're exactly right. Just trying to be nice. Your cat crapping outside is no problem, as far as I'm concerned. As long as you're standing there watching his every move, making sure he doesn't eat a chipmunk or a lizard, or--for the love of God--a bird. If we could only train them to eat non-native birds only. Some studies seem to indicate that they prefer native birds--or at least that native birds are more suceptible to cat predation. Anyway, this post isn't about feral cats, (because I'm tired of Hipparchia driving up here and punching me in the head), it's about exotic birds and reptiles.

I wonder sometimes that starlings and house sparrows get no love. Those common mynas (just a type of starling, really) are pretty good-looking birds, and really smart (probably part of the problem). Starlings too. I have a soft spot for them--you know they're just doing their jobs--it's our fault they've been put in the wrong place.

As far as ugly, unloved species being threatened by exotics? Our native mussel populations are extremely endangered by zebra mussels (and pollution and habitat destruction--that's another post), and most people couldn't care less. There are about a zillion species of tiny, non-descript fish that are being overwhelmed by goldfish and other introduced fish, and no one except ichthyologists seems to give a crap (or a carp). As far as birds--there seems to be a decline in populations of mourning doves (our most common native dove), and part of the reason could be competition from the bigger collared doves. A large percentage of our native songbirds are threatened by cowbird nest parasitism--cowbirds aren't exactly non-native, but human activity has allowed them to expand from their natural range on the Great Plains (where the other birds have learned to deal with them) to the rest of the continent. It's hard for me to think of any birds as ugly or unloved, but there are some (various sparrows and vireos) that people with, shall we say, a less developed avian aesthetic might think of as plain that are seriously threatened by cowbird expansion.

[Note--there is no such thing as a short answer to any question you ask me about birds.]

catnapping said...
This comment has been removed by the author.
catnapping said...

oooh. just reminded me of another invader introduced by foreigners (euro-americans, heheh)...Kudzu.

I remember one evening in Georgia...on a two-lane back road...had to pee, but was too scared to get outta the car.

hipparchia said...

pow! biff! whap!

hey, now, i've kept my icanhascheezburders? sentiments contained over at my own place recently.