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Tuesday, July 29, 2008

Dragonfly Swarm

When the weather is decent, I take my exercise early in the morning, riding my Cannondale bike along the Evanston lakefront. The bike path winds north along the eastern edge of the Northwestern University campus. Many years ago, NU created a greenspace by filling in a bit of Lake Michigan and creating a small penninsula. Since this "lakefill" juts out into the water, its environment differs from the "natural" lake front. There are lots of gnats and midges, seagulls and mosquitoes. As I was riding one recent morning, I looked around and realized that I was in the middle of a dragonfly swarm! It was eerie - the morning sun sparkled on their wings and you could hear them humming. I didn't realize the these bugs swarmed; here is a chunk of info I found when I sniffed around the web:

Several species of dragonfly are known to collect in large swarms. In most cases this appears to be due to very favorable feeding conditions in the area. It may also be a "courting" group with males actively searching for females. This is less likely as males are much more aggressive to each other when looking for a mate.

Some dragonflies gather in swarms before moving to a new area (like a bird migration). The reasons for this are unclear but may be due to population pressures. There are records from the US of migratory swarms.

For some reason, being in a dragonfly swarm was uplifting.........

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