Archive for the ‘natural science’ Category

Common Whitetail (mature male)

August 21, 2019

Common Whitetail dragonfly (Plathemis lydia) was spotted near the Painted Turtle Pond Environmental Study AreaOccoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is a mature male, as indicated by the white coloration of his abdomen, pattern of wing spots, and terminal appendages. He is perched vertically on the corner of a storage shed.

16 AUG 2019 | Occoquan Bay NWR | Common Whitetail (mature male)

This male has mated many times, as indicated by the scratch marks 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.

Gear Talk

“Expose for the highlights” is a well-known rule of thumb in photography, that is, adjust the camera settings so the highlights are exposed perfectly.

Mature male Common Whitetail dragonflies are challenging to photograph because they prefer perching in direct sunlight, so it’s easy to blow out the highlights on their bright white abdomen. After a few test shots, I was able to adjust the flash power ratio so that the subject is exposed properly.

Copyright © 2019 Walter Sanford. All rights reserved.

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Blown away!

August 19, 2019

A Common Whitetail dragonfly (Plathemis lydia) was spotted at the Painted Turtle Pond Environmental Study Area, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is an immature male, as indicated by his brown coloration, pattern of wing spots, and terminal appendages.

Gear Talk

“Expose for the highlights” is a well-known rule of thumb in photography, that is, adjust the camera settings so the highlights are exposed perfectly.

The preceding photo was a test shot. The highlights are almost blown out completely because the flash power ratio was set too high for proper exposure of the scene; the dragonfly flew away before I could reduce the flash power.

All of that being said, there’s something about this image that I like. It reminds me of an old, faded black-and-white photo print. The word “sepia” comes to mind.

Related Resource: Common Whitetail dragonflies (young males, mature males)

Copyright © 2019 Walter Sanford. All rights reserved.

Gray Petaltail dragonfly (female)

August 16, 2019

A Gray Petaltail dragonfly (Tachopteryx thoreyi) was spotted during a photowalk with Michael Powell around a small seep-fed pond in the forest at an undisclosed location in Prince William County, Virginia USA.

This individual is a female, as indicated by her terminal appendages. She is perched on a small tree in a sunny clearing.

21 MAY 2019 | PNC. William County, VA | Gray Petaltail (female)

A seep is a seep is a seep.

Gray Petaltail is known to occur at a small, seep-fed pond located in the forest. Part of the seep is shown below. The female dragonfly featured in this blog post was perched on a small tree just to the left edge of the photo.

23 MAY 2018 | PNC. William County, VA | seep in the forest

Forest seeps vary in size and associated vegetation, but wherever you find one it provides good habitat for petaltails and some species of spiketails.

Copyright © 2019 Walter Sanford. All rights reserved.

“Grays” love them some me!

August 14, 2019

2019 was a record-setting year for observing Gray Petaltail dragonflies (Tachopteryx thoreyi) with Mike Powell at an undisclosed location in Prince William County, Virginia USA.

  • 21 May 2019 was the day that we observed at least a dozen (12+) Gray Petaltail — the most on any day during 2019.
  • 14 June 2019 was the day that the most “Grays” landed on me, including one female and two males plus some others that didn’t perch long enough to be photographed by either Mike or me.

Female

The first individual is a female, as indicated by her rounded hind wings and terminal appendages. She is perched on the front of my gray-green shirt.

Photo used with permission from Mike Powell.

Please get this man to a barber STAT! On the other hand, there isn’t much else that can be done about the face. As you can see, I’m the owner of a high mileage “vehicle” — fortunately it still runs good!

Photo used with permission from Mike Powell.

Males

The next individual is a male, as indicated by his “indented” hind wings, and terminal appendages. He is perched on the right sleeve of my shirt.

Photo used with permission from Mike Powell.

The same male is shown in the following image. This photo is my favorite in the gallery.

Photo used with permission from Mike Powell.

The last individual, possibly/probably a male, is perched on my off-white bucket hat. The “Gray” was doing a Vulcan mind-meld with me by using specialized contact via the tips of his legs.

Photo used with permission from Mike Powell.

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

More “Grays” on me

August 12, 2019

Well, really just one “Gray.” Gray Petaltail dragonfly (Tachopteryx thoreyi), that is. Perched on my … er, hip. This individual is a female, as indicated by her rounded hind wings and terminal appendages.

Guest photographer Michael Powell shot both images during a photowalk with me on 21 May 2019 at an undisclosed location in Prince William County, Virginia USA.

The following photo set provides a brief example of what we call “working the shot.” The first photo is what some other ode hunters call the “record shot,” meaning get a shot, any shot of the subject in case it flies away and is never seen again.

Photo used with permission from Mike Powell.

Slowly Mike moved closer to get the shot he wanted, shown below.

Photo used with permission from Mike Powell.

The Backstory

21 May 2019 was a great day for spotting Gray Petaltail dragonflies during a long, productive photowalk with Michael Powell at two locations: along a small stream in the forest; and around a small seep-fed pond. At least a dozen (12+) T. thoreyi were observed during the day, including two “Grays” that landed on Mike.

As we were walking toward Mike’s car at the end of the day, I was feeling disappointed that we hadn’t taken any photos of T. thoreyi perched on me. That’s when I noticed a Gray Petaltail perched on a fence rail. Before I was able to take a picture of the dragonfly, she flew from the fence rail to a new perch on my backside. Fortunately Mike was close behind me and was able to shoot the good photos featured in this blog post. Needless to say, I suffered as the butt of many jokes related to my indelicate circumstance!

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

Habitat for Tiger Spiketail dragonfly

August 9, 2019

Millions of readers have acquired the secrets of success through The Magic of Thinking Big. Source Credit: Amazon.

One of the secrets of success when scouting good habitat for Tiger Spiketail (Cordulegaster erronea) is “the magic of thinking small,” as in small seep-fed streams in the forest.

What does the right habitat look like?

The following photos were taken during a Tiger hunt with Michael Powell along a small stream in the forest at an undisclosed location in Prince William County, Virginia USA. The photos are shown in sequence as we worked our way downstream from the headwaters. Mike and I have seen a single Tiger Spiketail patrolling this stream on two days during 2019: 01 July; and 06 August.

The first photo shows a seep in the forest at the headwaters of a small stream located along a segment of a marked trail in Prince William County, Virginia. Notice that skunk cabbage (Symplocarpus foetidus) and interrupted fern (Osmunda claytoniana) aren’t associated with this seep.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

The next photo is located a short distance downstream from the headwaters, looking back upstream. The stream channel is ~2-3 feet wide and no more than a few inches deep.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

A smaller “side seep” (upper-right) is a tributary of the same stream (foreground).

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

The last photo shows the view looking downstream from a point just below the small side seep. Although the stream seems to disappear near the bright sunlit patch on the forest floor, in fact the stream flows over the first in a series of mini-“waterfalls” that get progressively higher going downstream.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

What time of day is best for Tiger hunting?

Based upon field observations by Kevin Munroe, Michael Boatwright, and Mike Powell and me, Tiger Spiketail seems to have two time periods of increased activity that might be site-dependent: 10 a.m. to 12 noon; and 2 p.m. to 4 p.m. Mike Boatwright and I speculate increased activity might be associated with the time of day when a given site receives more sunlight. The Tiger at the site Mike Powell and I visited seems to be a “morning person.”

Do other odonates live in the same habitat?

Mike Powell photographed a Gray Petaltail dragonfly (Tachopteryx thoreyi) along the same stream on 10 July 2019. Now we know with reasonable certainty that Gray Petaltail and Tiger Spiketail can coexist in the same seep(s).

Mike also photographed a Twin-spotted Spiketail dragonfly (Cordulegaster maculata) on 16 April 2019 in a field near the mouth of the stream. Twin-spotted Spiketail larvae probably live in the stream itself, rather than the seeps that feed the stream.

Related Resource: Habitat for Tiger Spiketail dragonfly, featuring GoPro video showing another small stream where Tiger Spiketail has been observed in Northern Virginia.

Copyright © 2019 Walter Sanford. All rights reserved.

Eastern Ringtail reunion, continued

August 5, 2019

Whenever possible I prefer to photograph odonates against a clean background, such as the concrete pavement in my last blog post. In my opinion, a simpler background makes it easier for the viewer to focus on the subject.

In contrast, my photowalking buddy Mike Powell prefers a “natural” background (as opposed to man-made). Knowing Mike’s preference, I “influenced” an Eastern Ringtail (Erpetogomphus designatus) to relocate from his perch on a concrete sidewalk to a new perch on a grass lawn. Although the green grass complements the unusual color palette of the dragonfly, the viewer’s eye must work harder to find the subject.

This individual is a male, as indicated by his “indented” hind wings, and terminal appendages. He is perched on a grassy area in between concrete sidewalks surrounding a berm/observation area alongside the boat ramp, near the main parking lot at Riverbend Park.

Adult flight period

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for E. designatus is from May 16 to September 24. The species is classified as uncommon to common. Its habitat is “rivers.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for E. designatus seems to be longer than it is in reality. The adult flight period for a single site is probably shorter. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Eastern Ringtail is 09 June to 20 September.

Related Resource: Posts tagged ‘Eastern Ringtail dragonfly’

Copyright © 2019 Walter Sanford. All rights reserved.

Reconnecting with Eastern Ringtail

August 2, 2019

I used to be a science teacher at a public school where the building engineer had a great line for postponing and/or begging off maintenance work: “I’m only one man!” Well, when it comes to odonate hunting I have come to realize you can’t have it all — every year you need to make and prioritize a “target list” of species that you would really like to find/see and pass on many other old favorites.

For example, Eastern Ringtail (Erpetogomphus designatus). Although E. designatus is one of my favorite dragonflies, I had to pass on seeing them during 2018 in favor of hunting the elusive Tiger Spiketail (Cordulegaster erronea). It was good to reconnect with Eastern Ringtail recently during a brief photowalk with Michael Powell along the Potomac River at Riverbend Park in Fairfax County, Virginia USA.

The following photo set provides a brief example of what I call “working the shot.” The first photo is what some other ode hunters call the “record shot,” meaning get a shot, any shot of the subject in case it flies away and is never seen again.

Slowly I moved into position to get the shot I wanted, shown below.

This individual is a male, as indicated by his “indented” hind wings, and terminal appendages. He is perched on a concrete sidewalk around a berm/observation area alongside the boat ramp, near the main parking lot.

By this time in the ode hunting season, I was happy to be able to find the target species quickly and with almost no fear of pesty parasites such as chiggers, ticks, and mosquitos!

Related Resource: Posts Tagged ‘Eastern Ringtail dragonfly’

Copyright © 2019 Walter Sanford. All rights reserved.

Another female Gray Petaltail

July 31, 2019

This blog post features two of my favorite photos of another Gray Petaltail dragonfly (Tachopteryx thoreyi) spotted during a photowalk with Michael Powell along a small stream in the forest at an undisclosed location in Prince William County, Virginia USA.

21 MAY 2019 | PNC. William County, VA | Gray Petaltail (female)

This individual is a female, as indicated by her rounded hind wings, and terminal appendages. She is perched on a large tree in a sunny clearing.

21 MAY 2019 | PNC. William County, VA | Gray Petaltail (female)

In natural sunlight, the Gray Petaltail was nearly impossible to see against the tree bark. An external flash unit added enough “fill” light so that the dragonfly “pops” with detail!

Copyright © 2019 Walter Sanford. All rights reserved.

Odonate exuviae collecting sites

July 29, 2019

The following video shows a “boater’s-eye view” of some sites where odonate exuviae have been collected by Joseph Johnston along Aquia Creek, located in Stafford County, Virginia USA. Joe is an avid boater and sport fisherman who kindly agreed to be my “Eyes on the Aquia,” always on the lookout for odonate exuvia to share with me.

The first photo gallery features still images of several spots shown in the preceding video. Joe estimates the water is ~5-6 feet deep outside the channel markers, and much deeper in the middle of the creek.

Joe’s boat is somewhere between the long boat docks (lower-right quadrant) and Government Island (near center), as shown in an aerial view of Aquia Creek provided by Google Maps.

The last photo gallery features still images of several exuviae, shown in situ before Joe collected the specimens. The first photo shows where it all began, when Joe collected his first dragonfly exuvia for me on 20 June 2018.

Related Resources

Credits

All media Copyright © 2019 by Joseph Johnston. Used with permission from Mr. Johnston.

Copyright © 2019 Walter Sanford. All rights reserved.


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