Name that Species (If You Dare): Cygnus olor

I happened upon this worrisome sign while jogging through a little park in Christchurch the other day…

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(Thoughtfully edited by victim of attack?)

I continued my run on high-alert for signs of the fearsome fowl. I guess I was in luck, because I didn’t see any. But I realized this sort of encounter with wildlife warnings is a rare occasion here. It’s unlike North America, in that sense– here, you’ll never encounter signs about protective mama bears, or charging moose, or venomous snakes. New Zealand just doesn’t have that many dangerous creatures. So what’s the deal with the savage swans? I decided to investigate.

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Image courtesy of NZ Birds Online, credit to Peter Reese

Mute swans, or Cygnus olor, were introduced to New Zealand in 1866 because they’re so pretty. (Prettier than pre-existing New Zealand swans, you ask? Well, maybe. They actually hold their neck with a curvier, more elegant aspect than the native* black swan, and their quieter calls are less likely to disrupt a park’s tranquility than the noisy voices of the black swans. Swan attack doesn’t scream peace and tranquility to me– but the birds were introduced all the same.)

If you’re reading from North America, this story may sound familiar. Mute swans were introduced to the USA at around the same time, and for the same reasons. But here’s where the stories diverge. The swans flourished in the US, quickly outcompeting native waterfowl and spreading across wetlands. The population in New Zealand, however, has remained low. For comparison: in Michigan alone, the current mute swan population is estimated at 15,500 birds (and increasing at a rate of 10% every year!); in the whole of New Zealand, the population is just 200 birds. There’s a big difference in the amount of ideal swan habitat between those two areas, it’s true, but the discrepancy still seems stark. So why the difference in success between the two environments? It’s hard to find clear evidence. In New Zealand, some suspect botulism outbreaks are keeping swans in check; others cite predation pressure (remember our friend the possum? It’s a voracious predator on the eggs of native birds, which is a serious threat for native kiwi and parrot populations…but evidently it’s just as happy to chow down on swan eggs, too.).

In both the USA and New Zealand, mute swans can wreak considerable havoc on fresh and brackish waterways where they live and graze. As a result, the governments of both countries are invested in controlling populations. In the US, this takes more effort as wildlife managers actively hunt adults and destroy nests in attempts to curtail the swan’s successful invasion. In New Zealand, the government maintains the right to cull birds– but because the population stays so low, it doesn’t need to act on this right often.

And in both countries, there are ardent swan supporters working against this governmental management.  In the US, an organization called “Save the Mute Swans” claims that the mute swan is actually native, and uses dubious fossil record evidence and proposed migration routes from Russia to argue for its protection (the Department of the Interior remains unconvinced). In New Zealand, one organization has carried out repeated attempts to introduce a swan family to a lake in the Whaketane region. Curious readers can triumph along with the birds’ successes, and mourn with their failures when they follow along the multi-season attempt to establish a swan family at the lake.

To me, this seems like continuation of the same ideas that introduced the birds to New Zealand and the USA in the first place. I think of European fairy tales, classics like Swan Lake or Roald Dahl’s The Swan. There are strong cultural connotations that link swans with elegance, romance, and tranquility. In spite of their aggressive demeanor, the image of tranquility seems to be thriving.

Not so in Christchurch, however. The City Council is here to tell you: don’t get any sappy, romantic ideas with these swans! And watch your back while you run.

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I haven’t actually taken any pictures of swans in New Zealand…but I did get this shot of a dabbling duck  which connotes a similar sense of elegance, I’d say.

Where do you all fall on the swan spectrum? Do you think populations should be “managed” and reduced, or is the ineffable swan appeal enough to garner your support for their presence in public parks?

Until next time-

E.

*: Is it really native? Oh, it’s hard to say. Some black swans were certainly intentionally introduced from Australia, while others self-introduced. Swan populations that existed here even before the arrival of Australian black swans were once thought to be a separate species– now extinct– but are now thought to be members of the Australian black swan species just the same.  A reminder that assigning “native” and “non-native” is in many ways a murky process.

Sources:

https://www.allaboutbirds.org/guide/mute_swan/id

http://nzbirdsonline.org.nz/species/mute-swan

 

 

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