An Imperial Moth

While out for a walk through my butterfly plantation in the July twilight, I thought I saw a large yellow butterfly being attacked by a gray bird, probably a catbird. Several times the bird seemingly had it in its beak, only to have it break free again. Then they came through the bushes quite close to me and the bird saw me and flew away. The insect flew to a nearby tree trunk and landed, and looked more like a large moth. It also seemed sorta spastic, making little twitching and lurching motions.

So I slunk away and came up to the tree from the opposite side. Peeking around, I quickly cupped my hand over the moth and then maneuvered it between my cupped hands and held it captive for a few minutes. It apparently liked the darkness and the warmth because it calmed down except for little tremors, and when I slowly removed my upper hand, it didn’t fly away (this also often works for small frogs you want to observe).
It was an imperial moth, clearly a female, because they are noticeably larger than the males. Its right rear wing was tattered from bird bites, and there was a chunk missing from the back of its head, which I assume was also a bird bite. I took it into the carport and set it on a workbench for a closer inspection and it still didn’t fly away.

Two days later, it was still there, had laid four tiny eggs, and seemed dead, but if I picked it up it could cling to my finger. Crop dusters had been working around our neighborhood spraying insecticide, and I wonder whether the inevitable drift had damaged its coordination enough that a bird could catch it.

Holland’s moth book says that the imperial caterpillar is nearly omnivorous, while Mitchel and Zim specifically mention sassafras. I have dozens of young sassafras, both in sun and partial shade. I set the moth toward the inner part of a bushy one in partial shade, first on a flat leaf, where it couldn’t seem to get a grip, and then moved it to the petiole where it could cling and perhaps lay a few more eggs before it perished.
The next day it was gone, most likely eaten by some predator. If a chipmunk had climbed up the bush to get it, the wings would have been below. But nothing there, so a bird more likely took it away to a perch to feed.

I still had the four eggs, now firmly glued to the wooden workbench, and decided to move them onto sassafras leaves. These tiny yellowish spheres closely resemble those of the zebra swallowtail, which lays single eggs topside on pawpaw leaves near the petiole. So I chose them as my model.
Not wanting to damage the eggs, I used a chisel to peel up a thin slice of wood under each egg. Then using a tiny dab of wood glue, I attached each chip to a sheltered leaf as per the zebra model. Because the dab of glue might be a guide for some bird, I also put out about a dozen dabs without eggs as decoys. As of this writing a week later, and following a two-inch rain, three of the four could still be located and showed no change. Cool weather prevails right now and might be slowing their development.

And I encourage you to go out and about on conservation lands, especially those of Bur Oak Land Trust, because they are managed specifically as habitat. You never know what you might encounter, especially if you move slowly, quietly, and attentively.