As summer winds down, here are a few observations I’ve made or expect to make over the next few weeks.
Purple Traps
As I’ve traveled in Pennsylvania, Ohio and West Virginia this summer, I’ve noticed strange purple objects hanging in tree tops along major highways. They suggest a purple box kite.
In fact, they are traps intended to attract and trap emerald ash borers, the exotic, invasive insect that is destroying ash trees across their range.
A variety of state and federal agencies use these traps to assess the expansion of emerald ash borer distribution. The traps are triangular and each panel measures about 15-by-24 inches. The purple color, combined with chemical attractants, attracts the beetles, and adhesive surfaces on the inside trap the pests.
“The purple panel traps will not bring emerald ash borers into a noninfested site,” said Greg Hoover, ornamental extension entomologist in Penn State’s Department of Entomology.
“These traps help us determine if the pest is already there.”
Hummingbirds
The number of ruby-throated hummingbirds peaked at my house this week. Migration is already under way and the red-throated adult males were the first to leave.
But every morning a new wave of birds arrives and keeps the population high. My highest count was 13 hummers.
From summer banding studies, we know that represents about 20 percent of the local population on any given day. Multiply the largest number of hummers you see at any moment by five for an estimate of your total population.
In my case, that means as many as 65 hummers visited my feeders the last week in August. Hummingbirds will continue to move through the area for at least three more weeks, so do not stop feeding them.
Keep nectar feeders filled at least until the end of September or until you see no more hummers for at least a week. I keep my feeders up until mid-October.
(Nectar recipe: Mix one part table sugar with four parts boiling water, cool, and refrigerate.)
Swallow and swifts
Purple martins, barn, tree and rough-winged swallows, and chimney swifts have begun gathering in large pre-migratory flocks. Look for martins and swallows perched on power lines in open areas near water. It’s a great time to see several species side by side and study differences in size, shapes, and color.
Chimney swifts roost en masse in chimneys and abandoned smoke stacks. Active roosts are easy to identify because at dusk swifts gather in the sky above the stacks before descending to roost. A swift roost can contain dozens to hundreds of individuals.
Nighthawks
At early season high school footballs games, watch for common nighthawks sweeping the sky under Friday night lights. They’re catching insects attracted to the lights.
Nighthawks, kin to whip-poor-wills, are easy to recognize. Their uniformly dark bodies are marked by a single bold white bar on each wing. Though robin-sized, nighthawks seem larger because their wing span is about 40 percent wider than a robin’s.
Late nests
Over the last two weeks, I’ve received more than a dozen messages reporting a third brood of robins, Carolina wrens, bluebirds, and cardinals and wondering if this is normal.
Some birds such as chickadees, nuthatches, and woodpeckers raise only one brood per year. But many species raise multiple broods and when the weather cooperates and food supplies are abundant, three broods are not uncommon.
In the deep South, some species can pull of four or even five broods per year.
Ugly caterpillars
Finally, be alert for hickory horned devils, the caterpillar of the royal walnut moth.
By summer’s end, the body measures close to 6 inches long. Each segment of the green fleshy body is equipped with several short, black, spiny horns. The thoracic horns are the most fearsome.
These black-tipped orange horns can be up to three-quarters of an inch long and appear to be terribly dangerous. They are not.
After a summer of gorging on host tree leaves, the mature devils descend tree trunks to the ground, where they burrow into the ground to pupate.
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