Posts Tagged ‘Occoquan Bay National Wildlife Refuge’

When flat isn’t.

October 5, 2020

An Eastern Pondhawk dragonfly (Erythemis simplicicollis) was spotted along Delta Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is a female, as indicated by her green coloration and white terminal appendages.

15 SEP 2020 | OBNWR | Eastern Pondhawk (female)

The preceding photo was shot at an aperture of f/6.3 — notice the depth of field is a little too shallow at that f/stop to show the entire length of the dragonfly’s body in focus because she is perched on a small rock with her head/thorax a little higher above the ground than the tip of her abdomen.

Copyright © 2020 Walter Sanford. All rights reserved.

Veiled ventral view

October 2, 2020

Several Black and Yellow Argiope (Argiope aurantia) spiders were spotted during a photowalk with Michael Powell at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA.

15 SEP 2020 | OBNWR | Black and Yellow Argiope (female)

This individual is a female, as indicated by her size. The preceding photo shows a ventral view of the spider, slightly obscured by the thin veil of her web. Contrast this ventral view with a recent blog post featuring a photo of the dorsal view of another A. aurantia.

Related Resource: Arachtober, a Flickr group that’s sure to make your spider senses tingle!

Copyright © 2020 Walter Sanford. All rights reserved.

I’m the king of the world!

September 30, 2020

male Blue Dasher was spotted during a photowalk with Michael Powell along Deephole Point Road at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA.

15 SEP 2020 | OBNWR | Blue Dasher (male)

This male was perched about a foot above my head, observing all that passed before him along the road — reminds me of a scene from Titanic, the movie. “I’m the king of the world!

Copyright © 2020 Walter Sanford. All rights reserved.

Common Buckeye reminds me of fall.

September 28, 2020

Although there’s nothing common about the palette of colors for Common Buckeye butterflies (Junonia coenia), somehow it just works. I think their coloration seems to shout “fall.”

The preceding photo shows a Common Buckeye spotted during a photowalk with Michael Powell at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA.

Most of the Common Buckeye that Mike and I spotted seemed to be especially skittish — they flew away as soon as I moved into position to take some shots. This one was a little more cooperative, albeit poorly posed for a perfect photo. Oh well!

Copyright © 2020 Walter Sanford. All rights reserved.

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 (OBNWR), 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 (USA), 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

Note: Family Platystictidae (Shadowdamsels) is the fourth family of damselflies in the USA. Desert Shadowdamsel (Palaemnema domina) is the only member of this family. P. domina is rare, known to occur only in Arizona in the southwestern United States.

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.

An interactive version of the same species list is available from the Odonata Central Web site. The master list can be filtered in many ways. Location is perhaps the most useful filter.

For example, my good friend Mike Boatwright lives in Amherst County, Virginia USA. Click on the blue button labeled “Filter Results.” Then click the down arrow in the Location field, enter “Amherst” and select the complete location name that appears in a list of available options; click the “Apply Filtering” button. You should see a list of 97 species of odonates reported to occur in Amherst County, including 10 species in the genus Enallagma. Notice that Big Bluet isn’t on the list, although there are several species of Enallagma that aren’t found where I live in Fairfax County, Virginia USA.

Copyright © 2020 Walter Sanford. All rights reserved.

The old gray mare

September 23, 2020

A Great Blue Skimmer dragonfly (Libellula vibrans) was spotted during a photowalk with Michael Powell along Deephole Point Road at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA.

This individual is an old female, as indicated by her coloration and terminal appendages.

Oh the old gray mare
She ain’t what she used to be

Like a fine wine, she’s aged to perfection!

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 (OBNWR).

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.

Final Fine-lined Emerald

October 7, 2019

Several Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a photowalk with Michael Powell at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. At least six S. filosa were spotted along two dirt/gravel roads at the refuge; this is the last one we saw.

This individual is a male, as indicated by his “indented” hind wings and terminal appendages.

Decisions, decisions!

I shot 37 photographs of the following dragonfly perched in several places: two photos are out of focus; most of the rest are flawed in some way (in my opinion), for example I don’t like the background, or the composition, etc.

As it turns out, the last group of photos is my favorite. Within that group, I selected a subset of three photos that I like. Although the photos are similar, they are subtly different. I think one of the images is the clear winner, but I suffer from decision paralysis sometimes. The photos are shown in the order in which they were taken. Which one is your favorite?

No.1

No. 2

No. 3

Sidestory

I think I might have figured out the habitat/breeding habitat for Fine-lined Emerald dragonflies. As Mike Powell and I were walking along one of several roads at Occoquan Bay NWR that lead to hotspots for hunting Fine-lined Emerald, I noticed shallow pools of “black water” in the forest, beginning about halfway down one of the dirt/gravel roads at the park. I mentioned to Mike that I think the black water pools are habitat for S. filosa.

Sure enough, that’s exactly where we spotted the male featured in this post — the last one we saw as we were walking back to Mike’s car. It’s worth noting we have never seen a Fine-lined Emerald that far from the main hotspots. Mike saw several more S. filosa in the same area a few days later. Hey, I might be onto something!

Copyright © 2019 Walter Sanford. All rights reserved.

Great Blue Skimmer (old female)

October 4, 2019

A Great Blue Skimmer dragonfly (Libellula vibrans) was spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is an old female, as indicated by her tattered wings, gray coloration, and terminal appendages. The old gray mare, she ain’t what she used to be but she must have been a Betty back in the day — just look at those beautiful blue eyes!

Copyright © 2019 Walter Sanford. All rights reserved.

Common Buckeye butterfly

October 2, 2019

(Common) Buckeye butterflies (Junonia coenia) are relatively common at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. I notice them when I’m hunting for dragonflies and damselflies. They’re skittish usually, but if they cooperate I always stop for a few shots, especially when they pose against a background of complementary colors.

The Common Buckeye color palette is unusual, yet it just works. Who knew brown butterflies could be so beautiful? Definitely one of my favorites.

Copyright © 2019 Walter Sanford. All rights reserved.


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