Archive for the ‘education’ Category

Big Bluet damselfly (male)

September 25, 2020

A Big Bluet damselfly (Enallagma durum) was spotted during a photowalk with Michael Powell along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual — one of hundreds, if not thousands we saw while hunting for a rare to uncommon species of dragonfly — is a male, as indicated by his blue and black coloration and terminal appendages.

15 SEP 2020 | OBNWR | Big Bluet (male)

Ideal habitat for Big Bluet is as follows.

Habitat Large sandy lakes and lower reaches of rivers, even extending into brackish estuaries. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 2156-2157). Princeton University Press. Kindle Edition.

Think large, tidal rivers and bays. I have observed E. durum at Dyke Marsh Wildlife Preserve, Accotink Bay Wildlife Refuge, and Occoquan Bay National Wildlife Refuge.

Related Resources: Excellent digital scans created by Gayle and Jeanelle Strickland. Click on the button labeled “Download file” in order to view/save a full-size version of the graphics.

Sidebar: Scientific Classification of Damselflies

The following concise explanation of the scientific classification of damselflies is provided to help the reader understand where the genus Enallagma (American Bluets) fits into the bigger picture of the Order OdonataSuborder Zygoptera (Damselflies).

There are four families of damselflies in the United States of America, although only three families occur in the mid-Atlantic USA: Broad-winged damselflies; Narrow-winged damselflies (a.k.a., Pond Damselflies); and Spreadwing damselflies.

  1. Family Calopterygidae – Broad-winged Damselflies
  2. Family Coenagrionidae – Narrow-winged Damselflies
  3. Family Lestidae – Spreadwings

1. Family Calopterygidae is comprised of two genera.

2. Family Coenagrionidae is comprised of 14 genera. Three genera are common in Northern Virginia: Argia (Dancers); Enallagma (American Bluets); and Ischnura (Forktails).

3. Family Lestidae is comprised of two genera.

  • Archilestes (e.g., Great Spreadwing)
  • Lestes (e.g., Slender Spreadwing, Southern Spreadwing, Swamp Spreadwing)

There are relatively few genera of Broad-winged Damselflies and Spreadwing Damselflies. In contrast, there are many more genera and species of Narrow-winged Damselflies — more species, including many that look similar, makes this family the most challenging to learn!

Related Resource: “The Odonata of North America” is a complete list of both scientific names and common names for damselflies and dragonflies, maintained by the Dragonfly Society of the Americas.

Copyright © 2020 Walter Sanford. All rights reserved.

Eastern Pondhawk dragonfly (female)

September 18, 2020

An Eastern Pondhawk dragonfly (Erythemis simplicicollis) was spotted during a photowalk with Michael Powell along Deephole Point Road at Occoquan Bay National Wildlife Refuge.

This individual is a female, as indicated by her green coloration and white terminal appendages.

15 SEP 2020 | OBNWR | Eastern Pondhawk (female)

Look closely at the full-size version of the preceding photo. Notice the subgenital plate, a black upside-down “shark fin” located beneath abdominal segment eight.

Underneath Segment 8 there is either an ovipositor or a subgenital plate, depending upon the species [of dragonfly]. Both structures are for laying eggs and extend over Segment 9 and possibly beyond. Source Credit: Dragonflies of the North Woods, by Kurt Mead.

Remember that “Segment 8 and 9” refers to abdominal segments eight and nine (of 10), numbered from front-to-back.

Related Resource: Eastern Pondhawk dragonflies, a photo-illustrated guide to the identification of male- and female terminal appendages.

Copyright © 2020 Walter Sanford. All rights reserved.

Solanum carolinense wildflowers

September 9, 2020

I noticed some beautiful little wildflowers as I was photographing the Black and Yellow Argiope featured in my last blog post. Sometimes you need to stop and smell the “banana flowers.” Huh?

I maintain a simple text file called “Photowalking Field Notes.” After every photowalk or studio photo session, I record the date, location, photo gear, and of course, what I saw and photographed. Sometimes I see things that I’m unable to photograph (e.g., Tiger Spiketail dragonflies), so “saw” and “photographed” aren’t necessarily the same. Although I use keywords in both Apple Aperture and Adobe Lightroom, searchable text is a quick and easy way to find photos I have taken.

My field note for this photo is “light purple wildflower <– banana flower” because the yellow plant centers [insert correct name for plant anatomy here] remind me of a hand of bananas.

18 AUG 2020 | JMAWR | Solanum carolinense wildflowers

The preceding photo is simply a “record shot” of a wildflower I never noticed. I contacted “Plant Man Drew” Chaney for help with identification.

I met Drew at the Dragonfly Society of the Americas 2017 DSA Annual Meeting in Staunton, Virginia USA. Drew is an excellent all-around naturalist with considerable expertise in botany.

Drew quickly identified the wildflowers as Solanum carolinense. Most of the flowers in my photo appear a little past peak, based upon images featured on the reference Web page Drew provided. As always, thanks for your help, Drew — it is sincerely appreciated!

The Backstory

The wildflowers shown above were spotted during a photowalk with Michael Powell around Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) in Fairfax County, Virginia USA.

Copyright © 2020 Walter Sanford. All rights reserved.

Slaty Skimmer dragonfly (male, No. 2)

September 2, 2020

The following photo shows a Slaty Skimmer dragonfly (Libellula incesta) that was spotted during a photowalk with Michael Powell near Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) in Fairfax County, Virginia USA.

This individual is a mature male, as indicated by his coloration and terminal appendages.

18 AUG 2020 | JMAWR | Slaty Skimmer (male)

This mature male has mated many times, as indicated by the scratches on his abdomen.

Males that have mated often have marks on their abdomen where the female legs have scratched them. This is especially obvious in species in which males develop pruinosity, as the pruinosity on the mid-abdomen is scratched off, and the signs are visible at some distance. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 390-392). Princeton University Press. Kindle Edition.

Copyright © 2020 Walter Sanford. All rights reserved.

Blue-fronted Dancer damselfly

August 31, 2020

A Blue-fronted Dancer damselfly (Argia apicalis) was spotted during a photowalk with Michael Powell near Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA.

A. apicalis has “a blue form female and a brown form female.” Since neither the hamules nor terminal appendages can be seen clearly in the preceding photo, I’m unsure whether this individual is male or female.

Post Update

Michael Ready, good friend and fellow member of the Dragonfly Society of the Americas, shared the following comment via e-mail.

That’s an outstanding picture of a Blue-fronted Dancer. You state you are unsure of the individual’s gender. I am confident that it is a male. According to my field guides (Lam and Paulson), the blue-form female lacks the blue eyes and blue S8-10 that are apparent in your picture. Source Credit: Michael Ready.

Thanks for the kind words and helpful information, Michael! As it turns out, the field marks that you described are shown clearly in one of my blog posts: Blue-fronted Dancers (male, female), especially this photo.

Copyright © 2020 Walter Sanford. All rights reserved.

Great Blue Skimmer (mature male)

August 28, 2020

A Great Blue Skimmer dragonfly (Libellula vibrans) was spotted during a photowalk with Michael Powell around Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) in Fairfax County, Virginia USA.

This individual is a mature male, as indicated by his slightly tattered wings, blue coloration, and terminal appendages.

18 AUG 2020 | JMAWR | Great Blue Skimmer (mature male)

This male has mated many times, as indicated by the scratches on his abdomen.

Males that have mated often have marks on their abdomen where the female legs have scratched them. This is especially obvious in species in which males develop pruinosity, as the pruinosity on the mid-abdomen is scratched off, and the signs are visible at some distance. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 390-392). Princeton University Press. Kindle Edition.

Tech Tips

The preceding photo is full-frame (4,000 x 3,000 pixels), that is, uncropped.

The Panasonic Lumix DMC-FZ300 is one of two superzoom bridge cameras that I use as my “go to” rigs for photowalking. The minimum focusing distance in AF Macro mode is 1 m (3.3 feet) at maximum telephoto (600 mm, 35mm equivalent). My usual practice is to set the camera lens for maximum telephoto and move as close as possible to the minimum focusing distance, resulting in maximum magnification of the subject. That’s how I shot the photo shown above.

It’s worth noting the minimum focusing distance is 2 m (6.6 feet) at maximum telephoto when the camera IS NOT set for AF Macro mode. If your goal is to get as close as possible to the subject in order to fill the photo frame, then AF Macro mode is the way to go.

Copyright © 2020 Walter Sanford. All rights reserved.

Odonate Calendars (updated for 2020)

July 15, 2020

Phenology (noun) is defined as “the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.”

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summer); and Late Season (fall).

A calendar is a good way to visualize odonate phenology. I created a new blog page called “Odonate Calendars” (see right sidebar) that features several calendars showing the adult flight period for all species of dragonflies and damselflies that can be found in the Commonwealth of Virginia.

The page includes two interactive calendars for Dr. Steve Roble’s excellent datasets for the Commonwealth of Virginia: one for dragonflies; another for damselflies. Other calendars are provided under “Related Resources.”

Copyright © 2020 Walter Sanford. All rights reserved.

Sable Clubtail dragonfly (male, No. 2)

July 10, 2020

A Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted by Michael Powell during a photowalk at a location in Fairfax County, Virginia USA. This individual is a male, as indicated by his “indented” hind wings, and terminal appendages.

Look at the blade of grass on which the Sable is perched. Notice the “leftovers” from an afternoon snack eaten by the dragonfly before the photo was taken.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”); and a lower unpaired epiproct (“inferior appendage”). The epiproct for Sable Clubtail is essentially a wide plate with two prongs.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

The spiky green grass shown below is probably shallow sedge (Carex lurida) according to Drew Chaney, a.k.a., “Plant Man Drew.”

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Field Observations

All of the photos in the preceding gallery show male No. 2 perched on vegetation overhanging a small stream, enabling him to both hunt/feed and wait for an opportunity to mate with a female.

Natural History: Males perch on sunlit vegetation overhanging stream or on flat rocks in shade at head of riffle, fly up into trees when disturbed. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6102-6103). Princeton University Press. Kindle Edition.

In my experience, Sable Clubtails — both male and female — also perch on ground cover vegetation in sunny clearings near small streams. For example, see my recent blog post featuring male No. 1.

Sable does in fact fly up into trees when their “flight” response is triggered by overzealous photographers; they have been observed perched in trees as high as 20 feet above the ground. Be patient — usually they return to the ground soon afterward.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Sable Clubtail dragonfly (male, No. 1)

June 26, 2020

After a two-year hiatus since I spotted my first Sable Clubtail dragonfly (Stenogomphurus rogersi) during June 2018, it was a pleasure see an old friend again!

The first photo is the “record shot” for this individual, that is, “get a shot, any shot.” It is literally the first shot I took as soon as I spotted the Sable male. As you can see, he was looking in my direction so I was unable to sneak up on him. That proved to be problematic.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

I tried to move slowly into position for a lateral view of the dragonfly.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

The last photo is almost as far as I moved before Mr. Sable flew away — five shots and it was game over, man!

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Later the same day I  was fortunate to photograph a more cooperative male that will be featured in a follow-up post.

Rare to Uncommon

Sable Clubtail has a limited range and is classified as a rare to uncommon species of odonate. The following map shows all official records for Sable Clubtail in the United States of America.

DSA Distribution Viewer | Sable Clubtail

Source Credit: Abbott, J.C. 2006-2018. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: June 11, 2018).

Key: blue dots = Dot Map Project; green dots = Accepted records; yellow dots = Pending records.

As you would expect, there are few official records for the Commonwealth of Virginia, and fewer records for Northern Virginia.

The Backstory

A short segment of a small stream that flows through a park in Northern Virginia seems to provide ideal habitat for Sable. By the end of Summer 2018, the stream had been degraded significantly by siltation as a result of runoff from dirt that was dumped uphill from the stream.

The following year, the stream channel was almost completely choked by vegetation that I assume flourished in the nutrient-rich sediment that had flowed into the stream. Net result: One and only one Sable Clubtail dragonfly was observed by several spotters who visited the stream site during 2019.

That’s the bad news. The good news is I saw at least three Sable Clubtails when I visited the stream site on Saturday, 13 June 2020. That’s not as many individuals as I saw in 2018, but the species seems to have rebounded a little from the damage done to its habitat.

As Jeff Goldblum said in Jurassic Park, “Life finds a way.” Let’s hope!

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Arrowhead Spiketail dragonfly (male)

June 17, 2020

An Arrowhead Spiketail dragonfly (Cordulegaster obliqua) was spotted during a recent photowalk with Michael Powell at a location in Fairfax County, Virginia USA.

08 JUN 2020 | Fairfax County, VA | Arrowhead Spiketail (male)

This individual is a male, as indicated by his hamules and terminal appendages.

08 JUN 2020 | Fairfax County, VA | Arrowhead Spiketail (male)

The Backstory

At the end of a long day in the field, Mike Powell and I were walking back to the car slowly when we spotted a group of 10-or-so large dragonflies hawking insects over a HUGE field, near a small drainage pipe. We stopped to watch the hawkers hoping one would land; I sat on my Coleman camp stool to rest in the shade and enjoy the aerial acrobatics show.

One of the large dragonflies zoomed past Mike (he says he never saw it) and landed on a tall grass stem near the drainage pipe. It was the male Arrowhead Spiketail shown above!

Turns out the place is nothing like the habitat described as ideal (see below). I’ll say this: Three out of four times I’ve seen Arrowhead Spiketails, a fly-by was how I found them. So maybe just sit in a good spot and wait for the game to come to you. Maybe.

Habitat

Disclaimer: I have observed and photographed four (4) Arrowhead Spiketail dragonflies. I feel somewhat uncomfortable providing habitat guidance based upon a sample size of four. That being said, here goes.

Almost every Arrowhead siting had three common ingredients: a seep (or soggy place) in the forest, with skunk cabbage (Symplocarpus foetidus) and interrupted fern (Osmunda claytoniana); a small stream in the forest fed by the seep/soggy place; and a sunny clearing.

I found my first Arrowhead Spiketail at a small stream in Huntley Meadows Park. I walked the stream to its source, not that the source is well defined. Instead it’s a BIG soggy area. I wouldn’t call it a seep and I have never seen skunk cabbage anywhere in the park. There are two virtually identical streams elsewhere in the park where Arrowhead has been photographed. The male Arrowhead flew a LONG patrol along the stream, flying approximately six inches (6″) above the water level. At the end points of his patrol, he would hang up to rest in a sunny spot. It took a long time for me to find the hang up places!

Michael Powell spotted the second Arrowhead Spiketail I’ve seen, perched in a small, sunny clearing in the forest along a small stream. A seep with skunk cabbage and interrupted fern was located nearby. For what it’s worth, we saw/photographed several Gray Petaltail dragonflies (Tachopteryx thoreyi) in the same field.

MUCH FARTHER downstream, the same creek is a little larger in size. At one point, a small iron-stained creek flows into the main creek. Mike and I were standing at the mouth of the tiny creek when I saw an Arrowhead fly like a bat out of hell straight down the stream and turn left; it perched in a large, sunny field. I was able to find it, and we took photos. A week-or-so later, Mike traced the smaller creek to its source. Wouldn’t you know it? The headwaters are a seep with lots of skunk cabbage!

My most recent Arrowhead Spiketail sighting — the individual featured in this blog post — is the one that doesn’t fit the pattern. The dragonfly was spotted in a HUGE field of grasses, etc. There are small creeks and seeps nearby, but not within sight of the location where the Arrowhead perched.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.


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