10/25/2009

Beautiful, Bad, or Both?

salem end swan
This photo of an autumn swan reminded me of a topic I have been meaning to discuss for quite some time: Mute Swans.

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Mute Swans are an invasive species. Like Gypsy Moth caterpillars, Japanese Bayberry, and Norway Maples, Mute Swans are a non-native species introduced to this country by well intentioned human beings. Mute Swans were transplanted from Europe because of their beauty. They were placed in public gardens and private ponds all over the eastern United States in the 19th century. I've been thinking about Mute Swans being invasive ever since a respected colleague spoke about it months ago.

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I hate invasives. I have nightmares about Gypsy Moth caterpillars killing off all our deciduous trees; Japanese Bayberry choking the life out of all our native vegetation; and Norway Maples proliferating until their branches block out the sun. I even imagine these invasive species taking over the planet and leaving it uninhabitable other life forms!  Invasive plants and insects devastate the environment, and I hate Gypsy Moths and invasive plants with a passion. But Mute Swans?

young swan face
I like Mute Swans. I know that Mute Swans are problematic. Native swan species cannot compete with the larger, more aggressive, and more prolific Mute Swans. Other bird species that share habitats with Mute Swans are being driven from their nesting sites because Mute Swans are so intensely territorial. They have voracious appetites, and devour so much vegetation that some ponds and lakes are no longer able to support any life after Mute Swans lived there.

These are serious problems, but I don't hold Mute Swans responsible. As I see it, humans caused these problems by introducing birds into an environment that couldn't support them. Mute Swans didn't sneak over the border or bribe a customs official to get here. If anything, they were kidnapped!

I feel much the same way about Starlings and House Sparrows. I enjoy these bird species despite the fact that they are invasive and a problem. (I draw the line at Gypsy Moths, however. Gypsy Moths are utterly disgusting and repulsive, even if they were kidnapped!)

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The more I learn about Mute Swans, the more I like them! Are they aggressive? Yes. They are very aggressive and will inflict serious damage on birds, animals, and even humans that get too close. They are as territorial as the mockingbird that cleared my yard last spring (see post), but their massive size and great strength make them truly dangerous.

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I like aggressive birds, though. Especially BIG aggressive birds. Have I mentioned how much I like eagles, owls, osprey, hawks, and other such species? I practically fell in love with Great Black-backed Gulls after seeing one spear a shark, for god's sake!  Few birds are as bloodthirsty and aggressive as GBBGs!

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I admire the Mute Swan's loyalty to it's mate. These birds form long term pair bonds, which may not sound as dramatic as mating for life, but is just as impressive. The fact is that if a Mute swan loses a mate, they will mate again. They don't die of grief. They may choose to switch mates for no good reason, or try to have two mates at a time; but these are rare and aberrant behaviors. Basically they stay together as long as both are healthy. They raise multiple broods and care for their young for extended periods of time. It is not unusual for last years offspring to remain with the family even after a new family has been hatched.

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Mute Swans are a lot more monogamous than human beings. They are better parents, too. Most of their aggression stems from being protective of their families or potential families.

swan yoga
(I liked this youngster's attempt at yoga!)  I will probably be booted out of the 'true birders club' for this heretical posting. I won't recant, however. I know the presence of Mute Swans is bad for our local ecosystems, but don't ask me to dislike them because they epitomize invasives. The truth is that I like Mute Swans for themselves, without considering what they represent.  I truly regret that they are invasive. In this situation, there is no possibility of a happy ending all around.

1 comment:

  1. Super photos - and good discussion of the ambivalence around the Mute Swan. I am not thrilled by seeing them, especially when I know their numbers are squeezing native species. But I can't stay away from their grace and beauty - it is infectious.

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