Posts Tagged ‘Occoquan Regional Park’

Ebony Jewelwing damselfly (male)

July 30, 2021

An Ebony Jewelwing damselfly (Calopteryx maculata) was spotted along a small stream located in Occoquan Regional Park, Fairfax County, Virginia USA.

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

This individual is a male, as indicated by his all black wings and terminal appendages.

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

Habitat

It’s easy to find Ebony Jewelwing. Look for a small stream in the forest.

Slow-flowing woodland streams, usually associated with herbaceous vegetation. Tend to be more at rapids when that habitat is present. Occur on open banks when trees nearby (trees essential for roosting at night). May be abundant at small streams in woods where very few other species are present. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 1249-1251). Princeton University Press. Kindle Edition.

Copyright © 2021 Walter Sanford. All rights reserved.

Common Whitetail dragonflies

May 4, 2021

Common Whitetail dragonfly (Plathemis lydia) was observed near a small pond during a photowalk with Michael Powell at Occoquan Regional Park (ORP). This individual is a female, as indicated by her mostly brown coloration, pattern of wing spots, and terminal appendages.

28 APR 2021 | ORP | Common Whitetail (female)

Contrast the appearance of the female (shown above) with an immature male (shown below) seen on the same day at the same location. Notice the wing spots and terminal appendages are quite different for female and male Common Whitetail dragonflies.

28 APR 2021ORP | Common Whitetail (immature male)

Later the same day, another Common Whitetail dragonfly was observed near Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) in Fairfax County, Virginia USA. This individual is a mature male, as indicated by the white pruinescence covering his abdomen. “Common Whitetail,” the common name for Plathemis lydia, is derived from the coloration of mature males of this species.

28 APR 2021 | JMAWR | Common Whitetail (mature male)

Copyright © 2021 Walter Sanford. All rights reserved.

Common Whitetail dragonfly (immature male)

April 30, 2021

A Common Whitetail dragonfly (Plathemis lydia) was observed near a small pond during a photowalk with Michael Powell at Occoquan Regional Park (ORP).

This individual is an immature male, as indicated by his mostly brown coloration, pattern of wing spots, and terminal appendages. Part of his left fore wing is missing, probably as a result of an encounter with a predator.

28 APR 2021 | ORP | Common Whitetail (immature male)

Common Whitetail dragonflies are habitat generalists that can be found almost anywhere there is water. They are among the first species of dragonflies to appear during spring and the last to disappear in fall.

Copyright © 2021 Walter Sanford. All rights reserved.

MYN – Anisoptera exuvia (species unknown)

March 11, 2020

An Anisoptera exuvia (species unknown) was collected near a small pond at Occoquan Regional Park (ORP), Fairfax County, Virginia USA.

This individual probably is a member of the Family Libellulidae (Skimmers), as indicated by its anal pyramid. The small pond where the specimen was collected is perfect habitat for skimmers.

01 JUN 2019 | ORP | Anisoptera exuvia (dorsallateral view)

Related Resource: Another unknown species of odonate exuvia – a blog post by Walter Sanford featuring a “one-off” photo (that is, not a composite image) of the same specimen.

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Two photos were used to create a composite image: one photo focused on the head; and another photo focused on abdominal segments seven (S7) through nine (S9).

My Canon EOS 5D Mark II is a full-frame DSLR digital camera. RAW images are 5616 × 3744 pixels. The dimensions of the composite image are 5589 × 3743 pixels, that is, essentially full-frame. It’s usually necessary to crop composite images, at least a little, because the individual photos used to create the composite don’t align perfectly, even when the camera is mounted on a tripod (as it was in this case).

For what it’s worth, the following camera settings were used to shoot both photos: 100mm; ISO 100; f/8; 1/200 s; 0 ev. I need to tweak the settings a little in order to find the “sweet spot” for this camera/lens combo: the white background was slightly over-exposed; and the subject was slightly under-exposed. Of course that means I need to tweak the flash power for the backlights and add one or more additional external flash units for more fill flash. Overall, I’m fairly satisfied with the results of my first attempt using the MYN technique with this camera rig.

Copyright © 2020 Walter Sanford. All rights reserved.

What is it?

February 7, 2020

It’s time for another exciting edition of “What is it?” Well, what is shown in the following photograph? If you think you know what it is, then please leave a comment. The answer will be provided in a post update.

03 FEB 2020 | Occoquan Regional Park | What is it?

Post Update

Congratulations to the two readers who correctly identified the mantis ootheca shown in the preceding photo! (See Comments/Responses, below.)

This is a Chinese Mantis (Tenodera sinensis) egg case, as indicated by the distinctive roundish shape of the ootheca. Chinese Mantis is a non-native species.

Copyright © 2020 Walter Sanford. All rights reserved.

Skunk cabbage flowers

February 5, 2020

The following photo gallery shows skunk cabbage (Symplocarpus foetidus) flowers in a forest seep located at an undisclosed location in Fairfax County, Virginia USA.

This is ideal habitat for Gray Petaltail dragonfly (Tachopteryx thoreyi) larvae, and in fact, numerous adult “Grays” have been observed along a sunny trail near this location. Seeps are home for some species of larvae from Family Cordulegastridae (Spiketails) as well.

03 FEB 2020 | Fairfax County, VA | skunk cabbage flowers

03 FEB 2020 | Fairfax County, VA | skunk cabbage flowers

03 FEB 2020 | Fairfax County, VA | skunk cabbage flowers

03 FEB 2020 | Fairfax County, VA | skunk cabbage flowers

The last photo shows the same location during early Summer 2019. The plant with broad green leaves is skunk cabbage.

01 JUN 2019 | Fairfax County, VA | forest seep, with skunk cabbage

The following quote is perhaps the best description of a forest seep that I’ve read.

[Some] small tributaries … have their sources in numerous woodland seeps. While a few of these perennial springs bubble up out of the ground, most arise in moist hillside patches with lots of decaying leaf litter and luxuriant stands of skunk cabbage. Source Credit: White, Harold B., III. Natural History of Delmarva Dragonflies and Damselflies (Cultural Studies of Delaware and the Eastern Shore) (Kindle Locations 1213-1215). University Press Copublishing Division. Kindle Edition.

Related Resource: Skunk Cabbage: First Flower of the Year… by Alonso Abugattas, Capital Naturalist blog. The blog post includes an embedded link to an informative video by Mr. Abugattas: Capital Naturalist: Skunk Cabbage Blooming (3:58).

Copyright © 2020 Walter Sanford. All rights reserved.

Another unknown species of odonate exuvia

November 4, 2019

Another odonate exuvia was collected by Michael Powell during a photowalk with me on 01 June 2019 at Occoquan Regional Park, Fairfax County, Virginia USA. The genus and species is unknown.

Occoquan Regional Park | unknown species | exuvia (face-head)

This specimen might be a member of Family Libellulidae (Skimmers), as indicated by its labium (face mask) and pointy eyes.

Although this exuvia looks similar to the other one that Mike collected on 01 June 2019, it’s smaller and probably not another Slaty Skimmer (L. incesta) exuvia. Many species of skimmers are habitat generalists; the small pond where both exuviae were found is a perfect spot for many members of this family.

The photo (shown above) is a one-off, not a composite image. I plan to create higher quality composite images of this exuvia, shown from all viewpoints including dorsal, ventral, and lateral views. The composite images and one or more dichotomous keys will be used to attempt to identify the genus/species of the specimen.

Related Resource: Vimeo video: Identifying dragonfly larva to family (8:06).

Tech Tips

The following equipment was used to shoot the quick-and-dirty macro photograph featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); ISO 200; f/16; 1/180s.

Godox X2TF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control two off-camera external flash units set for radio slave mode: Godox TT685F Thinklite TTL Flash (manual mode); and Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode). Both flash units were fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the image.

Copyright © 2019 Walter Sanford. All rights reserved.

Unknown species of odonate exuvia (ventral)

October 21, 2019

This post features another photo of an odonate exuvia collected by Michael Powell during a photowalk with me on 01 June 2019 at Occoquan Regional Park, Fairfax County, Virginia USA. The photo is a one-off (not a composite image) showing the ventral view of the exuvia.

The genus and species is unknown. This specimen might be a member of Family Libellulidae (Skimmers), probably Slaty Skimmer (Libellula incesta).

Occoquan Regional Park | unknown species | exuvia (ventral)

Related Resource: Vimeo video: Identifying dragonfly larva to family (8:06).

Tech Tips

The following equipment was used to shoot the quick-and-dirty macro photograph featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-16 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); ISO 200; f/16; 1/180s.

Godox X2TF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control two off-camera external flash units set for radio slave mode: Godox TT685F Thinklite TTL Flash (manual mode); and Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode). Both flash units were fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the image.

Copyright © 2019 Walter Sanford. All rights reserved.

Unknown species of odonate exuvia, revisited

October 18, 2019

This post features more photos of an odonate exuvia collected by Michael Powell during a photowalk with me on 01 June 2019 at Occoquan Regional Park, Fairfax County, Virginia USA. Both photos are one-offs, not composite images.

The genus and species is unknown. This specimen might be a member of Family Libellulidae (Skimmers).

Occoquan Regional Park | unknown species | exuvia (lateral)

Mid-dorsal hooks are present on some abdominal segments. Lateral spines are located on abdominal segments eight and nine (S8-9).

Occoquan Regional Park | unknown species | exuvia (dorsal)

I still need to take close-up photos of the anal pyramid and shoot photos of the ventral view before I attempt to identify the genus/species of the specimen using one or more dichotomous keys.

Related Resource: Vimeo video: Identifying dragonfly larva to family (8:06).

Tech Tips

The following equipment was used to shoot the quick-and-dirty macro photograph featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-16 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); ISO 200; f/16; 1/180s.

Godox X2TF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control two off-camera external flash units set for radio slave mode: Godox TT685F Thinklite TTL Flash (manual mode); and Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode). Both flash units were fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the image.

Copyright © 2019 Walter Sanford. All rights reserved.

Unknown species of odonate exuvia

October 16, 2019

An odonate exuvia was collected by Michael Powell during a photowalk with me on 01 June 2019 at Occoquan Regional Park, Fairfax County, Virginia USA. The genus and species is unknown.

Occoquan Regional Park | unknown species | exuvia (face-head)

This specimen might be a member of Family Libellulidae (Skimmers), as indicated by its labium (face mask) and pointy eyes.

The photo (shown above) is a one-off, not a composite image. I plan to create higher quality composite images of this exuvia, shown from all viewpoints including dorsal, ventral, and lateral views. The composite images and one or more dichotomous keys will be used to attempt to identify the genus/species of the specimen.

Related Resource: Vimeo video: Identifying dragonfly larva to family (8:06).

Tech Tips

The following equipment was used to shoot the quick-and-dirty macro photograph featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); ISO 200; f/16; 1/180s.

Godox X2TF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control two off-camera external flash units set for radio slave mode: Godox TT685F Thinklite TTL Flash (manual mode); and Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode). Both flash units were fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the image.

Copyright © 2019 Walter Sanford. All rights reserved.


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