An Outdoor Dragonfly Workshop – Terry Thormin
This past Saturday I conducted an outdoor dragonfly workshop for the Comox Valley Naturalists Society. The event was advertised to the general public as well and about 25 people attended, including five children. For the middle of the summer this is a pretty decent attendance. The event took place at Little River Nature Park where there is a pond that supports a good population of dragonflies. In an earlier blog I mentioned that I had recorded a total of 18 species at the pond, but when I recounted recently I came up with 20 species. For such a small pond on Vancouver Island this is a very good diversity.
Of course a number of those species have been seen only rarely and even amongst the more common ones you can’t expect to see all of them on any one day. So when we got a total of 8 species this day I figured that the day was a success. More importantly we observed lots of behavior which gave me lots to talk about. The Common Green Darners were laying eggs in the stems of the water shield, and the Cardinal Meadowhawks were flying in tandem, dropping their eggs one at a time directly in the water. The diminutive Blue Dasher would perch on a blade of grass and then suddenly dart out to give chase to a much larger Blue-eyed Darner. Canada Darners hovered close to shore giving the photographers opportunities to try for in-flight shots and several Striped Meadowhawks were observed hovering and perching in the grass back from shore.
The best show thought was put on by the Merlin later in the afternoon when many of the people had left. The Merlin is one of the smaller falcons and it loves to hunt dragonflies, especially the Common Green Darner. I described this behavior in my earlier blog, but will go over it briefly here for those that did not read that blog. The Merlin perches on a bare branch near the top of a large conifer at the east end of the pond. When an opportunity arises it will launch itself from the tree and come barreling down the pond in pursuit of one of the darners. If it is successful it will fly back to the tree to devour its prey.
On one occasion this day, just after one of the photographers had taken some photos of a pair of Common Green Darners close to shore in the process of laying eggs, the Merlin swooped in and with outreached talons plucked the pair off the lily pad right in front of us. I have observed the Merlin going after darners in flight many times, but this is the first time I saw it take a pair of ovipositing darners. I now suspect that this must be the preferred prey for the Merlin. After all, ovipositing darners are like sitting ducks and you get two for one and I am sure even Merlins appreciate twofers.
I believe that Little River Pond is a good barometer for what is happening to dragonfly populations in this area and perhaps on the whole of Vancouver Island as well. Unfortunately, most dragonflies seem to be down in numbers and some species have been totally absent from the pond. The only species that seems to be doing well is the Common Green Darner, and this is a migratory species, so our resident population may have been augmented by migrants from the south.
As Annie has pointed out many times, butterfly populations on the island are way down, and my observations lead me to believe that other insect populations are suffering as well. It is hard to determine what the cause is, and it is highly unlikely that it is only one cause. I do know that without insects we simply would not survive. They pollinate about 80% of all flowering plants and are the source of food for most birds. What doesn’t eat insects eats those things that eat insects or eats the plants that insects pollinate. Our education system is failing badly when it comes to providing students with a proper insight into the importance of insects in the environment.
A recent report from North American Bird Conservation Initiative states that aerial insectivores in Canada are declining faster than any other group of birds, and the Barn Swallow and Chimney Swift are down to about a quarter of their 1970 population levels. It also states that on the pacific coast, where human settlement, forestry and industry are most intense bird populations overall have declined by 35%. Although this cannot all be attributed to a decline in insect populations, there is no doubt that this is a major factor, and if you consider loss of habitat as one of the factors in bird declines, you have to remember that loss of habitat also means a loss of the insects that inhabit that habitat.
I had not intended this to be anything but a report on the success of a dragonfly workshop, but somehow I managed to get sidetracked into talking about what we are doing to the environment. These conversations seem to occur quite regularly and I am convinced that, amongst my circle of friends at least, most people are becoming more and more concerned. Annie and I are trying through these articles to make people more aware of what is happening on Vancouver Island and elsewhere. It seems like a small thing at times, and we wonder if what we are doing will have any impact at all, after all it is big business and the government that need to change. But almost all big change starts from small beginnings, and we can only hope.