I spent most of today volunteering at Hawk Ridge up in Duluth, MN. As always I brought my cameras with and got some fun pics but for those you will have to wait for tomorrow. Most of the birds that we saw today up at Hawk Ridge were the smaller raptors; sharp-shinned hawks, kestrels and merlins. These birds are usually the first types of raptors that begin migrating south in the fall.A big reason that many of these birds begin to migrate, particularly kestrels and merlins is because they are following the migrating green darner dragonfly. The green darner migrates a lot like the monarch butterflies do. They head south in the fall to warmer climates where they will lay their eggs and then die. The offspring hatch and mature quickly, with in about three months, then they begin to head north and spring begins. Once they arrive back in the north they will lay eggs and then die and their offspring will begin the process again. There are many other types of darner dragonflies other then the green darner. There are 39 species of darners in North America and 500 different types of darners world wide. There has been very little study on migration for these other types of darners, but since most of them emerge later in the summer it is probable that they die when the winter cold arrives.
The darners are sub divided into several different genus. The largest genus are the blue darners. All of the blue darners, genus Aeshna, have two side stripes on their thorax. People who study Odonata, dragonflies and damselflies, use the shape, size and color of these side stripes to distinguish between the different types of blue darners.
From the shape of the side stripes I believe that this is a Canada darner. Canada darner are pretty common in my neck of the woods. They prefer a habitat with a lot of vegetation mixed in, like small green ponds, slow moving streams or the marshy shores of lakes. You can usually find them flying from the beginning of July through September, although I find that they are a lot easier to photograph in September. I have just begun to start to see blue darners around here this year, these pictures where taken at Carpenter Nature Center in September of 2008.