Invisible Voices

a voice for the voiceless

Mute Swans – scapegoat for the Chesapeake marsh grasses

We’ve heard the plot line a millions times before: humans import pretty / cute / exotic animals as lawn ornaments or conversation pieces, and are surprised when those animals integrate into the local population. The animals breed (*gasp!* how did they know how to do that?!) and before long there are not just a handful of the imported animals, but an actual population.

At some point someone gets it into their head that this is A Bad Thing, and the small population of the non-native species is seen as The Big Bad, and every effort is taken to eradicate that species from the area. It never works, but they never stop trying. The species becomes the scapegoat, because after all the humans don’t want to change their behavior, and so they’d rather blame another species for all the ecological damage.

In Maryland, there is a campaign against Mute Swans. The population had gotten up to a whopping 4,000 a few years ago, which must have put them at something like 0.01% of the bird population in Maryland. Maybe not even that much. But this was seen as too much by the state of Maryland. These birds were single-handedly destroying the marsh grasses of the Cheasapeake Bay! The native Marsh Grasses!

So in the past few years the Powers That Be, in their infinite (lack of) wisdom, have targeted the Mute Swans, killing as many as they can, and destroying as many eggs as they find. The Mute Swan population in Maryland is now estimated at 500.

And that, according to Maryland, is 500 too many. They all must die, to protect those precious grasses, because god knows, there’s not a single other species eating those grasses, and the human impact on the bay can’t possibly be a contributing factor.

The Potomac River, which empties into the Bay, is grossly polluted, with much of DC’s street-side run off and sewage overflow going directly into the river and thus the Bay. But no, that can’t have anything to do with the grasses, can it? It must be the sole responsibility of the Mute Swans.

At some point, we must take responsibility for our own actions, and the incredible damage we inflict on the environment around us. We need to stop blaming animals for existing. And part of that is going to require getting past the obsession with an ideal of a pure “native” ecosystem. When non-native species integrate into a local ecosystem, we have to accept that there is a new ecosystem, which includes these new species.

Ecosystems are not static, and they have a natural way of finding their own equilibrium, which doesn’t necessarily look the way humans decide they want it to look. The ideals of pure “native” ecosystems are absurd, and harmful. It isn’t animals like Mute Swans doing damage to the Chesapeake Bay, it is humans and our destructive pollution.


10 responses to “Mute Swans – scapegoat for the Chesapeake marsh grasses

  1. greentangle June 22, 2009 at 12:38 pm

    These can be very complicated issues as I’m confident you know, and I don’t think there’s always a definite answer. I generally agree with you that the root cause of whichever invasive/native issue you look at is humans, but in a sense trying to wipe out a species which people have introduced into an ecosystem IS people trying to take responsibility for their actions. After the fact, unfortunately.

    Would your reaction be different in the case of an introduced animal directly killing an animal species which was already there, as opposed to indirectly affecting other animals by taking over their niche or destroying their food source? Isn’t the end result the same?

    You’re right that ecosystems are not static, and picking one point in time at random and saying that’s the way it should stay is absurd (unless we pick the point before humans became an invasive species in North America–then I’m all for it!) but I’d worry that completely ignoring how an area exists right now could be used to justify any kind of destruction.

  2. Nancy June 22, 2009 at 4:49 pm

    Unless we are prepared to “. . . wipe out a species which people have introduced into an ecosystem” and include invasive humans we do not have the right to kill any other species.

  3. Deb June 22, 2009 at 5:20 pm

    @greentangle – it is very true that introduced species have an impact on the existing ecosystem, often to the detriment of the species that were already there. However, eradication of non-native species has never, to my knowledge, succeeded. Given time, a new equilibrium will be found in the altered ecosystem, with natural predators and diseases balancing out the newcomer’s population. Targeting the introduced species throws the ecosystem out of balance even more, preventing an equilibrium from being found. Deer have population explosions after attempts to diminish their numbers, because there’s less competition for resources, which triggers higher fertility. This is similar to what happens in all species, if not the mechanics, then the side effect.

    This is all just the biological/ecological perspective, and it is a simplistic one, because it is ignoring that even without introducing a non-native species, the given species in an ecosystem will go through ebs and flows. Right now the climate is shifting, and along with the shifting climate shifts the local ecology.

    Mute swans or no, the ecology is permanently altered, and it would have altered regardless of whether the swans had been imported.

    I’m not saying we should ignore the way ecosystems are now, and not protect them. I’m saying that killing of targeted species is not protecting the ecosystems. Millions of gallons of waste are being poured into the Potomac and ending up in the Bay every day. And the government spends its time and resources on 500 swans! The Chesapeake Bay, by the way, is gigantic. We’re not talking about a small little bay, we’re talking about the entire eastern shore of maryland, and coastal Virginia too. It’s a huge system. That the blame for the decline in marsh grasses is being attributed to 500 swans is absurd.

    And then there’s Nancy’s point, which I agree with 100%.

    Humans have messed up every single time they’ve had the arrogance to interfere, in the name of improving things. Half, or more, of the invasive species were introduced on purpose, to try to fix a different problem that we created. And it fails. The only exception to that that I know of is the dung beetle, introduced to Australia from Africa to take care of the problem of the sheep who were literally suffocating the australian farm lands in manure. Australia didn’t have a native species that could take care of the amount of shit that was being produced, and the dung beetle successfully took care of that.

    That’s the exception that proves the rule, really.

    And anyway, why do we think we know best? Why do we think we have that right to make those kinds of decisions?

    Maybe people have good intentions, but neither history nor science backs up these decisions. So it makes you wonder what the real motivation is.

  4. nothoney June 22, 2009 at 7:07 pm

    Great post, Deb. Every time I hear the story on NPR about mute swans I want to scream. I, too, agree with Nancy 100 percent. Why do humans persist in the belief that we are superior to every living thing on the planet? Nothing could be further from the truth.


  5. greentangle June 22, 2009 at 8:05 pm

    Deb, I agree with most of what you wrote although I’d question some of your first paragraph claims; but more importantly, I just don’t think it’s the whole story. As I wrote, I’m not a big fan of the whole native/invasive issue myself, and I’m also almost always opposed to killing.
    But . . .

    I don’t know for a fact one way or the other if an introduced species has ever then been 100% eliminated from an area. I’d certainly think it’s possible given that we’ve driven other species to extinction. But regardless, is 100% the only measure of success? Can’t whatever reduction we may cause in the population of an introduced species help prevent the extinction of a native species which might have disappeared if the introduced species was allowed to spread unchecked? Doesn’t that become not arrogance but a responsibility once we’ve screwed up in the first place?

    It seems to me the effect of your argument is to allow the initial interference with nature (assuming we’re talking about human-introduced invasives) but then claim it’s wrong to interfere with nature so we can’t try to correct the problem we created. So it’s ok for animals we introduced to kill the animals that were there, and we shouldn’t try to protect them? Why do we have the right to make that decision?

  6. Savannah Robillard June 22, 2009 at 8:11 pm

    Any one who decides to kill ALL the swans deserves a special place in Hell.

  7. Deb June 22, 2009 at 8:41 pm

    @nothoney that’s a good question. I have no answer.

    @greentangle, I studied this for a while in college, so when I say I have never heard of an eradication attempt succeeding, I mean that I couldn’t find a case when I was looking hard in the literature for one. (bio major) Every case discussed was a case of humans making things progressively worse with their fixes. The prof brought up the dung beetle, and it sticks in my mind so clearly, because it was a singular exception. I’ve never heard any different.

    Ecosystems are impossible to model. What if meddling to try to fix one mistake causes 10 species to go extinct instead of the 1 that had been in danger? It is as much a possibility as anything else. Humans think they know better of course.

    Once the initial interference has been done, the ecosystem is changed. It can’t be gotten back to the way it was before. (Of course ecosystems are always changing, so no surprise there.) Especially when you’re talking about mobile species. Birds fly. Keep out signs don’t work on them.

    As for whether it is okay for animals we introduced to kill the animals that were there, is that more wrong than the animals that were there being killed by other animals that were there? What’s the difference, precisely? And why do we have the right to decide who is allowed to kill who?

    We can’t control nature any more than we can predict it.

    But if protecting these native species is really the goal, why are 500 mute swans scapegoated (despite my sarcastic statement in my original post, they are not the only ones eating the grasses, they are not the sole cause of the grasses decline), when human-activity and human-pollution is what is killing the entire bay?

  8. greentangle June 22, 2009 at 10:01 pm

    Again I agree with much (I often mention killing deer as dealing with a symptom rather than the cause of the problem), but I’ll just focus on this paragraph and then let this go.

    “As for whether it is okay for animals we introduced to kill the animals that were there, is that more wrong than the animals that were there being killed by other animals that were there? What’s the difference, precisely? And why do we have the right to decide who is allowed to kill who?”

    Yes, I think there’s a huge difference between a natural predator-prey relationship which has probably evolved over centuries vs. killing done by a species which is only there because of human stupidity and which may very well lead to extinction. In the first case, I don’t think there’s anything wrong with it at all; in the second, it’s a human-caused death which you’d object to if the human did it directly.

    If there’s no difference who kills who, why exempt humans from the equation? Why does it matter whether swan eggs are destroyed by humans or raccoons, whether deer are eaten by wolf hunters or human hunters? Choosing to do nothing in the case of an introduced species is still very much assuming the right to decide who kills who.

  9. Deb June 23, 2009 at 6:13 pm

    The swans have been in the area for almost 50 years. They’re part of the ecology now, like it or not. They do eat small aquatic animals in addition to the bulk of their grain and grass diet, but they’re not exactly some big bad predator out killing a mess of other animals. They are seen as a danger to marsh grasses by the people wanting to justify their slaughter, and as I’ve mentioned before, it is a ludicrous claim given that they are NOT the only ones eating those grasses, and they are such a laughably small number. The state isn’t going out killing all the other animals who are also eating the marsh grasses, and as I mentioned, the swans have been a part of this ecology for almost 50 years.

    What you have is an area that can support a certain number of animals in their various niches. Humans are often out of touch with this, but left alone, that’s how it works. So you have swans, competing with other water birds, and the vast majority of the population is, by far, NOT swans. They’re not like starlings. What you seem to be saying is that it is okay for the other water birds to eat the insects and frogs and small fish along with the grasses and grains in the area, but that it is wrong for the swans to do the same. Kill the swans, and the other birds numbers increase, so the same general number of grass, grain, insects, frogs and small fish are being eaten. The other birds increase, not because the swans were killing those birds, but because of how nature and population density works, when it comes to resource competition.

    So it is a prejudice against non-natives. The swans, eating their natural diet, are not inserting an unnatural aspect into the ecosystem. The swans are not causing extinction. In fact, extinction is a rare side effect of non-natives. Unless you’re talking about humans, in which case massive extinction follows us everwhere we insert ourselves into the ecosystem.

    One reason that extinction is a rare side effect, even when the overall population balance is drastically changed, has to do with how exactly predator-prey relationships work, and how they change based on the changing populations of the prey. The most readily available prey gets preyed upon more frequently. The smaller populations are able to maintain their population, even if in a smaller number, because they have less pressure from predation.

    But don’t take my word for how this all works from a science perspective. You can read up on it. Look for Population Biology text books, classes, or whatever, and learn it for yourself. Behavioral Ecology would fit in as well.

    There is obviously a difference between humans destroying swan eggs just to destroy them, and raccoons after dinner.

    As for wolf vs human hunters, again, humans killing to kill, wolves after dinner. And yeah, some humans eat the animals they kill, but the point is they don’t need to eat animals to survive in the first place. It is gratuitous.

    We’re going around in circles at this point, so just as a fyi, I’m not likely to continue to respond further on this post. It is taking a lot of time, of which I don’t have enough.

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