Saturday, September 19, 2009

Farm Bulletin: Of Hornets and Men

Contributor Anthony Boutard has written eloquently about the wildlife, both vertebrate and invertebrate, that inhabit the fertile fields of his farm in the Wapato Valley and the graceful dance (a waltz? a tango? a tarantella?) that is required between a farmer and the native species that inhabit the land.

The showers Wednesday afforded an opportunity to mow the chestnut and walnut plat in dust-free comfort. We need to have low vegetation so we can find the nuts. At this time of the year, we run the tractor with the roll bar up, even though the operator gets a shower passing under low limbs, and a spiny chestnut burr or two in the lap.

This is yellow jacket and bald face hornet (above) season, and the plat always has a couple of yellow jacket nests in the ground, and an occasional a bald face hornet nest (left) on a low hanging limb. When disturbed, the wasps attack the highest point on the tractor; by instinct, they go for the head. The mower passed over two yellow jacket nests, the roll bar warded off the stings, and the locations were noted. It's now two days later and they are still on the alert. The bald face hornet nest is in the poplars adjacent to the plat, and is huge compared to other years.

These wasps are generally unpleasant to encounter, but they are also a valuable component of the farm's ecosystem, so we avoid killing them unless it is absolutely necessary. They kill a lot of harmful insect larvae. Social insects in the order Hymenoptera, which also includes bees and ants, but not termites, are described by the entomologists E.O. Wilson and Bert Hölldobler, as "super organisms." The wasp nest develops from a single queen who has survived over the winter. The nest's purpose is to generate as many queens as possible to over-winter and start nests the following spring. You will find the overwintering queens, large and mild mannered, in leaf litter, wood piles and any sheltered nook.

At this time of the year, the activity in the nest is feverish. Wasps are arriving and departing in a constant stream. They are bringing in fragments of fruit, aphids, caterpillars and carrion. They will even attack weak bee hives and have a yen for all manner fruit, especially grapes. For us they are a very minor irritation. The bald face hornets have more powerful mandibles, and seem to do more damage. Unless you stumble on the nest, the wasps are too busy with food collection to pay attention to nonfood matters. We are stung more frequently by honey bees. That said, a misstep can result in a dozen or more very painful stings. So we constantly scan for evidence of nests.

The yellow jacket meets it match in the skunk (right). Like the yellow jacket, the skunk is generalist. It belongs to the family Mustelidae, which also includes weasels, mink and badgers. Skunks are nocturnal and hide in burrows or under building during the day. From time to time, skunks will take up residence under the trailer that serves as our office. The skunk is a powerful digger, and will root yellow jacket nests. The animal is unbothered by the stings. They are pretty genial animals and give plenty of warning by stamping their feet before spraying. Unfortunately, some dogs never learn the cues. Although they will raid poorly constructed chicken coops, like the yellow jacket, skunks are a valuable part of any farm. Skunks mostly eat small rodents, grubs and adult insects.

And a final note (be sure to watch to the very end of the trailer):

On the 25th, 26th and 27th of September, the documentary "Ingredients" will be shown at the Bagdad Theater. Each night, the ticket sales will benefit a different local organization. These are: Multnomah County Food Initiative, Loaves and Fishes, and Ecotrust's Farm to School Program. We encourage you to see this documentary, as it has a lot of local Portland influence.

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