Friday, June 29, 2012

Virginia Dragonflies: The Calico Pennant

One of the dragonflies we saw the first morning in Virginia was the Calico Pennant.  This is a small dragonfly – smaller than our meadowhawks in Washington – but what it lacks in size it makes up for in appearance.  Through the binoculars this is a brilliant dragonfly, with intricate patterns in the wings and heart-shaped reddish spots lined up along the abdomen.  You can't fail to notice a Calico Pennant, and their high perching index of 80 - 90% ensures lots of good viewing opportunities.  Here are a few male Calico Pennants from Virginia:

One of the first male Calico Pennants we saw.  There's a lot going on in this small dragonfly.

Calico Pennants can look like a miniature saddlebags on the wing, but then you notice the extra spots on the wings.

A Calico Pennant stands out from its surroundings.

The wings and abdomen have interesting patterns and colors.  We never tired of looking at this dragonfly.

Pennants are named their habit of perching on the top of a stem and orienting themselves to face into the prevailing winds – just like a pennant at the top of a flagpole.

Wednesday, June 27, 2012

The Unexpected Pleasures Of Dragonflying: A High Tension Situation

Have you ever heard of a soap-powered boat?  The idea is this:  Take a small plastic toy boat, attach a piece of bar soap to the rear of the boat where you would normally have the outboard motor, place the boat in water, then sit back and watch the boat speed away just as if the soap actually were an outboard motor.  What's going on here?  The answer is surface tension.

Water has a fairly high surface tension.  When you place the toy boat in water without a soap motor, surface tension pulls on the boat equally in all directions – surface tension pulls the boat backward just as strongly as it pulls it forward.  As a result, the boat remains motionless.  Now attach the soap to the rear of the boat.  Soapy water has a lower surface tension than normal water, so now surface tension pulls the boat forward with a greater force than it pulls backward.  The boat takes off in the forward direction, pulled along by the stronger surface tension there.  Very nice.

What does this have to do with dragonflying?  Well, today Betsy and I were watching American Emeralds at Cranberry Lake.  Suddenly, a yellowish "caterpillar" fell out of a tree and landed in the water.  I think it may have been the larva of a sawfly, but I'll have to look into this in more detail.  In any case, after the larva landed in the water it began to move rapidly toward the shore.  It moved so fast, in fact, that it left a wake.  I looked at it through my binoculars, because I couldn't imagine how a caterpillar with its tiny legs could swim so rapidly.  What I saw was that the water at the rear of the larva looked a bit oily.  I think the larva secreted an oily substance, probably related to the web it spins to make a cocoon, and that this reduced the surface tension – just like a bar soap at the back of a toy boat.  The larva seemed to be using surface tension to speed it across the water, with no paddling required.  So far I haven't found anything about this online, but I'll look into it some more and let you know if I can confirm or debunk this notion.

Ahhh, you never know what you're going to see when you're out dragonflying.

Tuesday, June 26, 2012

A Convention of Cardinals In Anacortes

Betsy and I went to Smiley's Bottom in downtown Anacortes yesterday.  We weren't expecting to see that much, based on the recent low activity level at Cranberry Lake.  Instead, we were pleasantly surprised to find a convention of Cardinal Meadowhawks in full swing.  Now a group of cardinals who choose the pope is called a college or a conclave, but I think a convention of cardinals suits our meadowhawk friends.  The convention consisted of several male meadowhawks staking out prime territory along the edge of a pond, and a few pairs in tandem dipping in the water to lay eggs.

Cardinal Meadowhawks are incredibly colorful – a treat for the eye.  In addition, they have a perching index of about 90%, meaning they spend 90% of their time perched waiting for prey or a mate.  This makes them an ideal subject for close observations with binoculars or a spotting scope, and for photographs as well.  Just find a favorite perching site of one of the males, position yourself nearby, then wait for him to return and put on a show for you.  Here's one from yesterday that landed just inches from me.

Cardinal Meadowhawk (male).  The small yellow dots on the abdomen are a holdover from his days as a teneral, when he was mostly yellow.

Notice the concentrations of dark red color near the base of the wings.  This is a key field mark for these dragonflies.

Young dragonflies like this one have "blank expressions" in their eyes.  As the eyes mature they become more transparent and show noticeable pseudopupils.

Cardinal Meadowhawks are easy to ID.  First, they are intensely red.  Once you get to see the red of a Cardinal Meadowhawk it's pretty easy to recognize it when you see it again.  Second, they have a concentration of dark red color at the wing bases.  This feature distinguishes the Cardinal from all other meadowhawks in our area, and is readily visible from almost any angle.

As mentioned above, Cardinal Meadowhawks generally lay eggs in tandem.  They hover low over the water, then gently dip down to immerse the tip of the female's abdomen, at which point she releases a few eggs into the water.  Here are a couple shots showing the egg laying in action.

Cardinal Meadowhawks flying in tandem, preparing to lay eggs.

The actual process of laying eggs is quite gentle in Cardinal Meadowhawks.  Female Autumn Meadowhawks don't have it so easy.

Other dragonflies at Smiley's Bottom yesterday included a single Four-spotted Skimmer and several California Darners.  One of the California Darners was seen to do a spin-dry, something we've seen them do several times so far this year.

Sunday, June 24, 2012

Virginia Dragonflies: The Comet Darner

Betsy and I were in Virginia last week for a family get together.  Of course, we were also hoping to see some interesting birds and dragonflies while there – and we weren't disappointed.  As luck would have it, our hotel was located next to some nice wildlife areas, including a pond and some woods.

The morning after arriving we visited the pond, and immediately saw lots of dragonfly activity – many individuals and many species as well.  One of the first dragonflies we saw was the strikingly-colored Comet Darner.  This darner has a reddish-orange abdomen and a green thorax and head.  It's unmistakable, which certainly makes the identification a breeze.  Here are a couple shots of it, first in flight, and then perched in a tree:

A Comet Darner (male) patrols its pond.
Comet Darner perched high in a tree.
Notice the long, orange legs.  No wonder the species name for this dragonfly is longipes, meaning long-legged.

The Comet Darner is larger than the Common Green Darner, which was also seen at the same pond.  In fact, the Comet Darner is the second largest dragonfly in North America – exceeded in total length only by the Giant Darner of the southwest.

The Common Green Darner and Comet Darner are closely related, both belonging to the genus Anax (king, ruler).  The Common Green Darner's scientific name is Anax junius (king of June), while the Comet Darner's scientific name is Anax longipes (long-legged ruler).  The robust legs seen in the last photo above show how this darner got its name.

Sunday, June 10, 2012

California Darner

The earliest, and smallest, darner in our area is the California Darner.  Here's a shot from my recent trip to Cranberry Lake:

California Darner, male.  You can clearly see the "egg tooth" on the front of its thorax, which it uses to break through the larval skin when it emerges as an adult.

Notice the lack of a front stripe on the thorax, the cream-colored spots on the tenth segment of the abdomen, and the simple (blade shaped) appendages – all key features of California Darners.  Also notice that it is perched on the ground, another characteristic of these darners.  The other common darners in our area – Blue-eyed Darner, Paddle-tailed Darner, Shadow Darner – almost always perch in a bush at hip to shoulder height.  In our area, a darner on the ground is quite likely to be a California Darner, especially early in the season.

There were a dozen or more California Darners flying over the meadow and landing on the ground at Cranberry Lake.  When you walk through the grass you flush another darner every few steps.  At one point I saw a pair in tandem being chased by a single  male.  The lone male grabbed the male in tandem and they crashed to the ground.  The photos below show the pair in tandem and the lone male sitting on top.  After a few moments the male in tandem took off, displacing the lone male, and the pair flew high up into the trees.

A male California Darner on top of a pair in tandem.  Apparently it was trying to break up the pair so it could replace the original male.

The pair stays attached and takes off, displacing the lone male.

Saturday, June 9, 2012

Four-spotted Skimmer

One of the dragonflies seen a couple days ago at Cranberry Lake was the Four-spotted Skimmer.  Here's a photo of one from that day:

Four-spotted Skimmer, male.  Notice the dark spots at the nodus (center of leading edge) that give this dragonfly its name.  The dark spots near the wing tips (the stigma) don't count, since all dragonflies have them.  Also, note how the front two legs are folded up and tucked behind the head, just as they are during flight.

Four-spotted Skimmers have a high perching index (about 80 – 90%), and hence are easy to observe and photograph.  If you see a golden brown dragonfly in our area it's almost certainly a Four-spotted Skimmer, so the ID is fairly easy as well.  Females look the same as males, except a bit duller in color.

Mating is a rapid affair with these dragonflies.  Their short, pudgy abdomens aren't particularly flexible, and hence they stay in the wheel position for only about 10 to 15 seconds.  After mating, the female dips the tip of her abdomen repeatedly into the water to lay eggs while the male hovers above for protection.  They don't stay attached in tandem during egg laying, as do many meadowhawks, because their inflexible abdomens aren't well suited for that kind of maneuver.

Thursday, June 7, 2012

Anacortes – The New Emerald City?

It's well known that Seattle goes by the nickname "The Emerald City," but yesterday Anacortes had reason to use that name as well.  It was home to at least two American Emeralds, a small dark dragonfly with beautiful green eyes.  Here are a couple photos:

American Emerald, male.  Notice the single white ring hear the base of the abdomen.  Ringed Emeralds have white rings at the base of each segment along the abdomen, and Mountain Emeralds have no white rings at all.

American Emerald, male.  Notice the shape of the abdomen – it starts narrow, widens out, and then narrows again near the tip.

The emeralds were at Cranberry Lake, where I saw my first dragonflies in Washington State this year.  In addition to the emeralds, there were several Four-spotted Skimmers, and a dozen or more California Darners.

The emeralds are about the same size as Four-spotted Skimmers, but they are much darker and skinnier in flight.  Also, they look "deep chested" – that is, the thorax seems oversized in comparison with the rest of the body.  When they fly toward you their eyes give an unmistakable flash of green.

The common emeralds in our area are the American Emerald, the Ringed Emerald, and the Mountain Emerald.  The American Emerald is distinguished by having a single white ring near the base of the abdomen, as you can see in the photos above, whereas the Ringed Emerald has white rings at the base of each segment of the abdomen.  See the following link for a look at a Ringed Emerald:

In contrast, the Mountain Emerald has no white rings on the abdomen, but instead has golden stripes on the sides of the thorax.

As you can see in these photos, American Emeralds like to perch on the ground.  They have a rather low perching index (perhaps around 50%), but with patience you can follow them until they land and get a great view.  Seeing those eyes close up is worth the wait.

Tuesday, June 5, 2012

Cardinal Meadowhawks: An Early Dragonfly

The three most common meadowhawks in our area are the Cardinal Meadowhawk, Striped Meadowhawk, and Autumn Meadowhwak.

Cardinal Meadowhawks are the first to fly, appearing as early as mid May.  Striped Meadowhawks become common in July, and Autumn Meadowhawks show up in numbers in August.  By the way, the Autumn Meadow is our latest flying dragonfly – hence its name – and it can be seen well into November.

The photos below are of Cardinal Meadowhawks in Vacaville, California in late May.  If you see a red dragonfly in our area in the next several weeks it'll probably be a Cardinal Meadowhawk.  The best field marks for Cardinal Meadowhawks are white spots on the side of the thorax and dark concentrations of red at the base of the wings.  Look for these marks in the following photos:

Cardinal Meadowhawk, male.  Notice the white spot on the thorax and the dark red at the base of the wings.  The four white spots are often hard to see when covered by the wings, as here, but the dark red in the wings is almost always visible.

Cardinal Meadowhawk, male.  One of the four white spots on the thorax is visible, as is the dark red at wing base.

Cardinal Meadowhawk, immature female.  The tiny egg scoop near the tip of the abdomen shows it's a female, and the white spots and dark red in wings shows its a Cardinal.  This individual will become slightly more colorful as it matures.  Teneral (freshly emerged) meadowhawks are often yellow, and become red with age.

In the field, male Cardinal Meadowhawks are intensely red.  Sometimes it's hard to believe a living creature can be that colorful – when you see one you'll know what I mean.

Saturday, June 2, 2012

A New Damselfly

On our way home from Arizona, Betsy and I stopped at the Black River outside Olympia to see if there might be any early River Jewelwings out and about.  There weren't.  However, we did see another interesting damselfly.

First, Betsy saw a female, which was deep reddish orange.  It looked like an immature forktail, since they are often an orangish color, but not one that was familiar to me.  A short time later we saw a male, which was clearly a new forktail for us.  It was the Swift Forktail.

Here's the male.  Notice the long blue tip at the end of its abdomen.  Also, this forktail prominently displays the "forked tail" that gives the group its name.

Swift Forktail, male.

The female almost looks red from a distance.  It has the same structure of thorax stripes as the male.

Swift Forktail, female.