Canada Darner

The darner family of dragonflies can be identified by their large eyes which come together in a long line at the top. Many other types of dragonflies eyes meet only at a single point. Their huge eyes give them the appearance that they are wearing a helmet. Darners are large dragonflies and they are very strong flyers.
These are Canada darners. They are part of a group of darners that are often refereed to as blue or mosaic darners. To distinguish one mosaic darner from another you often have to look at the shapes of the side stripes. In this case the small notch in the middle of the front side stripe as well as the small backward flag at the top of the front side stripe are the field markings that identify these as Canada darners. The pair in the photo below are in the process of mating. All dragonflies mate using this wheel type of position.

Canada Darner

It is pretty easy to tell if a dragonfly is a member of the darner family. Darner dragonflies have large eyes that come together in a long line. They are often described as looking as though they are wearing a helmet. Unfortunately when it comes to distinguishing one darner species from another it is not usually so easy. Several species are very distinct, however those that are what are often referred to as blue or mosaic darners can be very difficult to identify.
One of the most difficult is the Canada darner. It is very similar to the green striped and lake darner. The way to identify the species is to look at the two stripes on the side of the thorax, called side stripes. In the photos above you can clearly see a notch in the front side stripe of each dragonfly. If this notch is greater then 90 degrees then it is probably a green striped darner, If it is less then 90 degrees then it is probably a lake darner, if it is 90 degrees then it is probably a Canada darner. There are other things such as size, and the existence and thickness of a rearward flag at the top of the front side stripe. In the bottom photo the pair of Canada darners are mating.

Darner Invasion

Most of the dragonflies up here in Minnesota are gone. Our cold nights have for the most part finished off the season. That is not true everywhere in the U.S. however. Yesterday while a football game between Miami and Kansas State was postponed due to a storm, Sun Life Stadium, where they were playing, was invaded by a cloud of dragonflies. If you would like to read more here is a link.
It was hard to tell exactly what type of dragon that they were from the pictures that were provided but they appeared to be a member of the darner family. The Canada darner, pictured above, is one of the most common darners that we see around here. In the second photo the darners are mating. Shortly after the picture was taken she flew off back to the water to lay her eggs.

Wood Lake Nature Center

Yesterday turned out to be a fabulous day weather wise, so I decided to go out and take some pictures before an afternoon dinner with Michelle's family. Since my time was limited I decided that it was best to stay in the Twin Cities so I went out to check on some of my favorite haunts including Wood Lake Nature Center. The visitors center was closed due to the holiday, but the park was open and occupied with quite a few visitors.
I was encouraged to see quite a few signs of spring. Insects have begun to spring up now that the weather has gotten a bit warmer. There were already plenty of flies and box elder bugs flying around. A few green darner dragonflies had completed their northern migration and were chasing the small flying insects in the fields and mourning cloak butterflies were warming their wings in the sun. Mourning cloaks over winter in their adult butterfly form, that is why they are usually the first butterflies that you can see in the spring. Soon they will mate and then pass from the world making way for their offspring.
The first warblers of the year have also arrived. Yellow-rumped warblers seem to be everywhere. Warblers are typically insect eaters so they do not usually return until after the bugs do. Since yellow-rumps do not typically migrate as far south as most other warblers they are usually the first to arrive in the spring, as well as the last to leave in the fall.
Canada geese have already begun to nest. They usually nest on islands of reeds in the middle of the lake. This gives the nest some protection from predators like fox and coyote. Then they use many of their own down feathers to line the nest, making a soft feathery bed for the eggs.
Much of Wood Lake Nature Center is occupied by Wood Lake and adjacent wetlands. The lake itself is very shallow, only a couple of feet deep in many locations, and has a boardwalk running through the middle of it.There are wood duck houses that have been placed around the lake, as well as in some of the parks other water features, to provide nesting habitat for cavity nesting ducks such as Wood Ducks. Because the correct habitat is carefully maintained it is possible to see wood ducks in the park almost any time that you want to visit.

It is not only wood ducks that take advantage of the wood duck nesting boxes though, hooded mergansers are also cavity nesters and frequently will take over nest boxes in the park. During mating season both male and female can often be seen floating on the lake but later on in the summer the males will move off leaving the female to raise the family.
The turtles were also out enjoying the sun and the warm weather. Turtles are reptiles and as such are cold blooded. So they rely on the sun to warm them up which helps them to move better, digest food and fight diseases. They use logs, rocks, or any other make shift platform to bask in the sun, often piling on top of each other, or staking, in order to get more sun.
With dinner time approaching I decided to make my way back to the parking lot. On my way I noticed this great egret flying across the beautiful blue sky. I think that perhaps he had the same idea and was heading off to his in laws for dinner, but I doubt that it was ham and German potato salad.

Canada Darner

Most of the blue darner dragonflies are difficult to distinguish because they look very similar. Usually the only field marks to tell them apart are the side stripes on the thorax. Perhaps no two look as much alike as the Canada and green-striped darners.

Both types of darner have a notch in their front stripe as well as a rearward extension extending back from the top. The difference between the two is the angle of the notch on the front stripe. If the notch is deep, greater then 90 degree then it is a Canada darner, if the notch is shallow, less then 90 degrees then it is a green striped. The back stripe of both types is not notched at all. You can see the notch on these is pretty deep so I would guess that these are Canada darners. I photographed them at the Carpenter Nature Center in September. The second photo is an excellent example of a wheel, which is how dragons mate. They can actually fly pretty well even when they are locked together like this.

Darner Dragonflies

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.