Monday, October 9 2006
It was a beautiful warm October day, with temperatures back in the 70s after what had seemed a prolonged sabbatical into 50s and low 60s territory. The cold stones of the walkway pulled water out of the air and darkened with moisture. The air didn't seem particularly humid, but those rocks had lots of stored-up coldness. I had so much hot water stored up that I ran hot solar-heated fluid through the basement slab for the first time this season. Its temperature gradually rose from 59 to 60 degrees Fahrenheit, though this might have been partly due to the warmth of the day. At some point I found myself up on the solar deck, painting some of the new lumber used to support the vacuum-tube-based solar collector. Meanwhile Gretchen was mowing the lawn with the push mower, perhaps for the last time this season. I don't really have a good sense of how cold weather descends at this time of year; last year I was in the Holy Land while the season was engaged in the mid-autumn transition.
There still are some katydids lethargically chirping away after dark, but once temperatures fall below 55 they stop entirely.
There are no more Yellow Jacket Hornets at this time of year, but on warm days there are plenty of wasps, lady beetles, and assassin bugs flying around. These are three insect species that spend their Octobers looking for sheltered places to overwinter. Back when our house had plenty of exposed insulation, it was common to find hundreds of them (both alive and dead) mixed up in the fiberglass.
As for the hummingbirds, they've been gone for at least a week and any decrease in the level of the sugar water in the feeder is due to efforts of the most enterprising of post-summer insects. The hummingbirds, along with other other colorful tropical birds such as Baltimore Orioles, have returned (or are in the process of returning) to their ancestral homelands to the south.
It's interesting how the temperate-dwelling mindset of bird enthusiasts and scientists made it difficult to understand bird migration until they overcame their biases (fairly recently). If one assumes that hummingbirds and orioles evolved in temperate zones and consider them their homelands, as the birders and scientists do, then it makes little sense for them to migrate to the tropics when winter approaches. If they evolved here, why can't they just stick it our here? Why go south and compete with all the birds living down there year round? Once you realize that all these migratory birds actually evolved in the tropics, then their behavior makes perfect sense. When warm weather comes to the temperate regions, they quickly move into them, build nests, and raise families, exploiting a temporary extension of tropical habitat. When cold weather returns, they flee back to their homelands. Migratory birds in the tropics reportedly live very low-key lives while on "tropical vacation," keeping quiet and not interacting with others of their species. They've become specialists at exploiting the temperate summer, so they have no need to do anything other than exist when in the tropics.
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