Silk and Snow

(Searching for Saturniidae cocoons during a southern Ontario winter)
Article & Photography
by Tim Dyson

This article is dedicated to all other moth addicts, and all who appreciate the real world, the natural world.

After a long winter of feeding the local eagle population, and then a few weeks of eagle and raven observation and photography, I noticed the weather forecast called for many days of very warm temperatures and some rain.

I knew that in a day or two, my observation blind would melt, as it was made of snow for the most part. It had been erected on the ice of a frozen beaver pond, which would soon flood and wear thin.

I had rented a cabin for the winter in order to finish a book I started writing last year on Great Gray Owls. I had also taken enough photographs and notes to begin a book on the eagles I was feeding, and another book about the Barred Owl that showed-up one night at my cabin. We became well acquainted over several days and nights. (I believe I will be writing for a while).

During the late afternoon of March 8th, I decided to take a walk and look for a more permanent location for a wooden blind on dry land. I knew I could continue feeding the eagles, as there were still a few more weeks of potential winter, and the eagles would remain in the area for a while yet.

I walked along one of the many snowmobile trails that meander through the wild country, in hopes of spotting a nice, dry, exposed area for another blind. After walking for nearly half an hour, I stopped at a fork in the trail and pondered my options. I had already taken turns at three different forks, and it was getting dark. I did not want to wind up lost after travelling almost two kms from the road.

I sat down for a minute on an oak log, and considered a return to camp. I looked up to check for any sign of a glowing sunset penetrating an otherwise overcast sky, and found myself staring at a nice fat Promethea Moth cocoon.

I immediately jumped up and took a few photos. Though quite large, and probably of a female, I noticed that it was very weathered and gray, and that the valve had been pushed open by the eclosion of the adult moth. The silk holding it to the branch had even started to unravel, and it dangled from the twig.

The old empty cocoon on the right shows signs of weathering and age, with its silvery-grey colour, and loose silk-wrap mooring. The (live) one on the left still retains its leaf-wrap and is much browner and secure.

Realising that it was the largest promethea cocoon I had ever seen, and might well have once held a female moth, I had an exciting thought: "What if she had emerged from this cocoon, attracted a male that afternoon, bred, and then began depositing her fertile eggs right here in this little grove of cherry saplings? Her offspring would have feasted right here, and maybe spun up cocoons here too."

I took a look around, and not two meters from the old cocoon was a nice fresh-looking, brown cocoon, which also was quite large. I was quite pleased, and remembered the many hours I had spent last winter searching for cocoons of Hyalophora cecropia and Hyalophora columbia, only to find none.

I walked in tight circles around the area of these two finds, and in a short time, found a smaller, rich-brown promethea cocoon. It seemed to have a heavy, live pupa inside as well.

Then, to my total amazement I found an old empty cocoon of a cecropia. All four cocoons were within a four meter radius. I took some photos of each in the departing light, collected them, and headed back to my cabin. It was still light enough to see my own footprints along the trail, so I was no longer worried about getting lost.

An old, empty Hyalophora cecropia cocoon, found near three Callosamia promethea cocoons amongst pin cherry saplings in an oak/pin forest clearing.

Two days later, I got up and did a few simple chores, and decided to go for another walk, only this time, locating more cocoons was my intent, and feeding and photographing eagles moved to the back of my mind. I walked a short distance, and took a different fork in the trail.

I did not get far, when my cell phone rang in my pocket. It was my friend Mike who had just arrived in town from Saskatoon. We had made plans to look at some of the local birds in the area, and he would be staying at my place for a few days. I told him that I was way back in the bush looking for cocoons, and he seemed quite interested. Just as I began describing to him what I was talking about, I spotted a large cecropia cocoon (live), not two meters from the trail!

Two Hyalophora cecropia cocoons, low to the ground, typical of my findings. The one on the left is old and empty. The one on the right is new and heavy with a live pupa. The two were only about twenty-five meters apart and were very near Callosamia promethea cocoons. The cecropia cocoons had been buried in deep snow for much of the winter.

Mike got quite enthusiastic, and suggested he help me look for more cocoons during his stay. I agreed. The more help the better, and it would be fun searching together, as it was a reasonably new activity to both of us.

A small group of wild black cherry saplings (foreground) provided six promethea cocoons. The lower, wetter area in the background yielded cecropia cocoons, attached to very low shrubs and weed stalks. The larvae may have fed on cherry, and, once matured, wandered some distance to spin.

I walked the area for another hour, and before I returned home, had found another cecropia (empty), and twelve more promethea cocoons! Some contained live pupae. Some had already hatched, and a few had dried-up larvae inside, which made a dry rattling sound when shaken, rather than the heavy clunk heard when shaking a live healthy cocoon.

At one point, I was lured some distance to something at the edge of a bog, something that I thought to be another cecropia cocoon. It turned out to be an old misshapen nest of Red-eyed Vireo creation. Through time, it had fallen to a somewhat vertical position, and closely resembled a cecropia cocoon.

Mike arrived next day and after lunch and exchanging bird stories through conversation and photographs, we headed out to a nearby area that I knew contained many Wild Black Cherry saplings. We walked for quite a while, enjoying the scenery. The first Red-winged Blackbirds were flying overhead, as well as the first Canada Geese of the season. We decided to turn back as it was getting dark, and we still hoped to find some cocoons before nightfall.

As we reached the main trail again, we saw by the light of the rising near-full moon, two promethea cocoons, dangling from the tips of cherry branches, looking quite like ornaments on a Christmas tree. With a dark backdrop of thick White Pine, they glowed a ghostly white, illuminated by moonlight that shone from behind us.

We were quite excited when we found that both contained plump, live pupae! For another twenty minutes we walked the area, checking all of the cherry saplings we could find, all the while a pair of Saw-whet Owls sang their dusk duet across a small marsh to the west.

We found three more promethea cocoons before it was just too dark to search anymore. We called back to the owls with our own imitations of their sounds. They soon responded and flew to the side of the marsh nearest to us. We crouched and peered through branches, but never did see either of the little owls. We walked home with another good story of the natural world.

In the dim light of a winter evening, a promethea moth cocoon hangs like a silver ornament, featured by reflections from the rising moon. There will be two or three more lunar cycles before the moth takes its first flight.

Next morning we decided that it would be a good idea to go back to the area and look for more cocoons in better light. After about an hour, we had found ten more promethea cocoons.

Most were located less than two meters above ground, and near the tips of branches.

One, the largest so far, was more than four meters up, and Mike climbed the tree and retrieved it.

Two days later, I returned to the area to do a little birding, but found I was soon consumed with checking many groves of cherry saplings for cocoons again. I found six more promethea cocoons, but all were empty old ones.

In the image above, the two cocoons at bottom-center (marked with red dots) show the range of size of what I have been looking for. On the right, is a large cecropia, the small promethea on the left, is only 2.3 cm long.

I decided to ban cocoon searches for the next day, as I was getting little else done. I went for a drive in the morning to see what birds I could observe. As I puttered down a narrow back road, there at the edge of the lane was a cecropia cocoon! I could not seem to get away from them. I checked, and it was empty.

I will no doubt continue to search for more, as long as the snow stays, (cocoons tend to contrast nicely against a backdrop of snow if they are low enough).

I have yet to figure out the right clues for finding cocoons of Antheraea polyphemus, and Hyalophora columbia, but will stay at it, and update this article if I am successful.

If there is one thing I learned from this adventure, it is that to be disappointed with finding only an empty cocoon here and there, may not be the best idea.

Continue searching the area, because as the saying goes; The fruit does not fall far from the tree.