Monday, September 21, 2009

THE HUMMINGBIRD AS PREDATOR


I saw a hummingbird catch a flying insect today. I think it was a male Asian Woolly Aphid (females don't fly.), but I’m not certain. They look like bits of lint floating through the air rather than flying insects. (See the picture.) It’s because they are so tiny all you see is the light hitting gossamer wings.

That hummingbirds eat enough insects to make up 40 percent of their diet, I already knew. Every creature needs protein, especially those with hearts that beat a thousand times a minute. But I never seen a humming bird in its active role as a predator.

One of the Ruby-throated hummingbirds was hovering at our feeder, sipping the sugar water, when the tiny insect leisurely floated by. The bird rose and hovered, watched the whitefly a moment as it moved away, then zipped over and snatched it from the air.

As Yogi Berra is supposed to have said, “You can observe a lot by just watching.”

Friday, September 18, 2009

The Homliest Bug



A few nights ago I went out on my back porch, just to sit in the dark and think. As I sat down, there was a buzzing sound by my chair I remembered hearing the first time in childhood. I stepped to the door and turned on the porch light.

Sure enough, is was a cicada. The name is a direct derivation of the Latin cicada, meaning "buzzer." We called them “jar flies” here in East Tennessee when I was a child, but some of the old folks still called them “locusts,” as in “seven year locusts” or “fourteen year locusts,” in reference to their habit of emerging in cycles in huge numbers.

In addition to the big cycles, there are always some that emerge every year to sing their mournful song, produced by vibrating specialized organs called “timbals” along the sides of the abdomen. Locals get used to the sound but last year, a visitor from California was fascinated by the sound.

I don’t know the species of the one I saw on the porch or even the species of the ones that come out in large numbers during seven and fourteen year cycles. I do know they are ugly and clumsy, like giant houseflies – up two inches in length -- with a huge eye on each side of their heads and tree smaller eyes. Dogs, cats, birds and other predators feast when a large cycle emerges.

For the cicadas between large cycles, it must be like arriving at a family reunion where most of the guests didn’t show up – when the nymphs emerge from the ground, climb a tree and shed their outer skins.

Other than being a periodic source of protein for predators and even human beings in some places, the big, ugly and clumsy bugs always make me wonder why they exist. There is a reason, though. You can bet on that.

Monday, September 14, 2009

SPOTTING THE BLUE-TAILED SKINK


Twice this summer I’ve spotted Blue-tailed skinks – once just outside the basement door and once on my deck. When I was a child growing up, we called these little lizards “scorpions.” I have no idea why they were called that.

Neither did I know as a 10-year-old that the dark body with yellow stripes running down the body to the end of the blue tail was the sign of a very young Blue-tailed skink. I assumed that the colorful ones were males and the reddish brown ones were females.

After all, colorful males are the standard in the world of birds. It was years before birds and dinosaurs were scientifically connected, but that was my youthful conclusion. I was wrong, though. Males become reddish brown and lose their stripes as they age, while females keep the blue tail.

What I did know was that their tails would break off and keep wriggling if you grabbed one. I also concluded they have some sort of tie with other individuals because I once caught a big, brownish skink (maybe four inches long) and put it in a commercial size glass jar, the kind pickled eggs come in, then put the jar under a crack in the wooden porch of our house where I had seen another skink peeking out earlier.

When I came back, the blue-tailed lizard had fallen or jumped into the jar. I thought they were mates, though I now know it was a young blue-tail and an adult male. Maybe they were related or maybe the young one was curious just as the young of other species are curious. I freed them later.

Blue-tailed skinks (Cryptoblepharus egeriae) are common in the Eastern part of America. They are predators, eating small insects and burrowers that maintain more than one entrance to there homes for safety. Mostly, I know they are gorgeous when they pause, with alert black eyes looking for danger.