Posts Tagged ‘Mocha Emerald dragonfly’

Walking tour of CAHH parks

November 26, 2018

Hollin Hills is a development in Fairfax County, Virginia, about 10 miles outside of Washington, D.C. It has about 450 houses. It was designed by Charles Goodman and developed by Robert Davenport.” Source Credit: “Hollin Hills” website (no longer online).

The Civic Association of Hollin Hills (CAHH) owns and maintains seven small parks in the community: the Wildlife Sanctuary; Sutton Potter Park; Brickelmaier Park; Charles Goodman Park; Paul Spring Park; “Mac” McCalley Park; and Voigt Memorial Park.

All of the parks are located along streams except Sutton Potter Park and McCalley Park. The Wildlife Refuge/Sanctuary extends from Woodlawn Trail to the dogleg in the road at Boswell Avenue and Delafield Place. Two parks straddle creeks that are tributaries of Paul Spring, a stream that runs along Paul Spring Road: Brickelmaier Park runs from Popkins Lane to Paul Spring Road; Goodman Park runs from Marthas Road to Paul Spring Road. Paul Spring Park runs along Paul Spring from the intersection of Rebecca Drive and Paul Spring Road to the intersection of Rippon Road and Paul Spring Road, directly across the street from McCalley Park and Voigt Park. The upstream end of Paul Spring Park is near White Oaks Park, a mid-size park maintained by Fairfax County Park Authority.

Sutton Potter Park was featured in an article that appeared in Washingtonian Magazine, “Best of 2004: Sledding Hills.” I shot two photos from a viewpoint about halfway up the long hill: one looking downhill; another looking uphill. Trust me, neither photo provides a sense of the true steepness of the hillslope — a sled ride downhill could be either extremely exhilarating or very terrifying! The park entrance is located at the 7400 block of Range Road; another entrance is located behind the townhouses along Windbreak Drive.

The Wildlife Sanctuary is (or was) a good place to look for Mocha Emerald dragonflies (Somatochlora linearis). Peak activity was observed during July. A segment of Paul Spring, a stream located in Paul Spring Park, is (or was) good for Needham’s Skimmer dragonflies (Libellula needhami); the entire length of the stream is good for damselflies, including Ebony Jewelwing (Calopteryx maculata) and Variable Dancer (Argia fumipennis)/Violet Dancer (Argia fumipennis violacea).

The Backstory

During Fall 2010, I used my Apple iPhone 3G and an app called “EveryTrail” to create an interactive map showing the location of the entrances to the CAHH parks. At some point, I noticed the hyperlink to the interactive map stopped working.

As it turns out, ownership of “EveryTrail” transferred to “TripAdvisor” in 2011; EveryTrail was acquired by “AllTrails” in 2016.

All of the interactive trail maps that I created eight years ago survived two ownership transfers, much to my surprise! Some of the interactivity of the original maps was lost in translation, but hey, all is not lost. “Walking Tour of CAHH Parks” is the current iteration of the interactive map, available from AllTrails. See also “Walking Tour of Huntley Meadows Park (Ver. 2).”

Tech Tips

The “EveryTrail” app was used to record a GPX file that traces the route I walked.

Photos were shot at selected waypoints. All photos featured in both interactive trail maps were taken using the built-in camera of my Apple iPhone 3G; the photos were geotagged automatically by the iPhone’s GPS receiver.

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More Mocha males

July 20, 2018

Nearly two weeks after my last visit to Huntley Meadows Park in search of Mocha Emerald dragonfly (Somatochlora linearis), I revisited the small forest stream in search of Mocha exuviae.

No luck finding exuviae, but hey, I decided to make lemonade from lemons and photograph a couple of Mocha males that hung up near each other, especially since there were noticeably fewer S. linearis in contrast with my last trip to the site.

Male 1

Both individuals are male, as indicated by their “indented” hind wings and terminal appendages.

Male 2

Copyright © 2018 Walter Sanford. All rights reserved.

Mocha male

July 10, 2018

The following photos show a Mocha Emerald dragonfly (Somatochlora linearis) perched alongside a small stream in the forest at a remote location in Huntley Meadows Park, Fairfax County, Virginia USA.

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

Mocha Emerald appears dark and featureless when viewed with the unaided eye in the shade of the forest canopy. More detail is revealed with added light from a fill flash.

Copyright © 2018 Walter Sanford. All rights reserved.

When Mocha flies

July 8, 2018

Many Mocha Emerald dragonflies (Somatochlora linearis) were spotted along a small stream in a remote location at Huntley Meadows Park (HMP), Fairfax County, Virginia USA. Most of the creek is shaded by the forest canopy — the perfect habitat for Mocha and mosquitos, a primary food source for all species of odonates.

05 JUL 2018 | HMP | Mocha Emerald (male, in flight)

Both individuals are male, shown hovering in flight above the water. Mocha Emerald males patrol back-and-forth along a short segment of the stream, stopping to hover in place sometimes.

05 JUL 2018 | HMP | Mocha Emerald (male, in flight)

Adult flight period

The adult flight period  for Mocha Emerald is from 16 June to 16 September (peaks in July-August), according to records for Northern Virginia maintained by Kevin Munroe, former manager at Huntley Meadows Park. In my experience, July is Mocha month in Northern Virginia.

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, a zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, 22 June to 10 October is the adult flight period for Mocha Emerald.

Copyright © 2018 Walter Sanford. All rights reserved.

Mocha Emerald terminal appendages (female)

September 29, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted by Andrew Rapp in Henrico County, Virginia USA. This individual is a female.

Terminal appendages

All female dragonflies have a pair of cerci (superior appendages) that have little or no function. The hind wings of female Mocha Emerald dragonflies are rounded.

21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)

(See a full-size version of the original photo, without annotation.)

21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)

(See a full-size version of the original photo, without annotation.)

Notice the subgenital plate shown in the preceding photo.

subgenital plate: plate below S8 that holds bunches of eggs when enlarged; variable enough in shape to be of value in identification. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11723-11724). Princeton University Press. Kindle Edition.

“S8” refers to abdominal segment eight. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Oviposition (egg-laying)

The following Apple iPhone 3GS “raw” video clip shows a female Mocha Emerald dragonfly laying eggs by the process of oviposition. The process typically lasts a few seconds to a few minutes. This individual was spotted on 16 July 2011 during a photowalk through the “Wildlife Sanctuary,” one of seven small parks in the community of Hollin Hills, Fairfax County, Virginia USA.

Mocha Emerald dragonfly (female, ovipositing) [Ver. 2] (0:23)

Related Resource: Mocha Emerald terminal appendages (male).

Editor’s Note: Sincere thanks to Andrew Rapp for permission to use his still photographs.

Copyright © 2017 Walter Sanford. All rights reserved.

Adios Mochacho!

September 1, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted along a small creek at a remote location in the forest at Huntley Meadows Park. This individual is a male, as indicated by his terminal appendages and hamules.

The Dragonflies of Northern Virginia Calendar of Flight Periods by Kevin Munroe, former manager at Huntley Meadows Park, shows the adult flight period for Mocha Emerald is from the second week in June through mid-September.

In my experience, July is prime time for Mocha Emerald in Fairfax County, Virginia USA. I spotted many Mochas during a visit to the same location during the second week in July. In contrast, the male featured in this post was the only Mocha Emerald spotted during an intense search along the stream. So it may be time to say “Adios Mocha-cho — see you next year!”

Copyright © 2017 Walter Sanford. All rights reserved.

Mocha Emerald dragonfly claspers

July 13, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted along a small creek at a remote location in the forest at Huntley Meadows Park. This individual is a male, as indicated by his terminal appendages and hamules.

All 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”).

09 JUL 2017 | Huntley Meadows Park | Mocha Emerald (male)

(See a full-size version of the original photo, without annotation.)

09 JUL 2017 | Huntley Meadows Park | Mocha Emerald (male)

(See a full-size version of the original photo, without annotation.)

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the following annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates.

hamules: paired structures that project from genital pocket under second segment and hold female abdomen in place during copulation Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11618-116198). Princeton University Press. Kindle Edition.

09 JUL 2017 | Huntley Meadows Park | Mocha Emerald (male)

(See a full-size version of the original photo, without annotation.)

Related Resource: Mocha Emerald terminal appendages (female).

Technique Hint: Did you notice that the “focus” of each photo (not to be confused with the focus point) is shown against a lighter background? That’s no accident — I composed each shot that way. As a result, the terminal appendages (cerci and epiproct) are much easier to see in the first two photos than the last shot, in which the composition highlights the hamules.

Copyright © 2017 Walter Sanford. All rights reserved.

Can I see some eye-dentification?

March 20, 2015

It may seem like all dragonflies look alike when you’re beginning to learn how to identify dragonflies. For example, all dragonflies have large, multifaceted compound eyes. Look closely. Careful observation of the color, shape, and size of eyes should enable you to quickly identify the family (or families) of dragonflies to which a specimen may belong.

The following field markers — used in combination with a good field guide to dragonflies, a species list for your location, and the process of elimination — should enable you to identify unknown specimens more quickly than randomly trying to find a match between your specimen and one of the 316 of species of dragonflies known to occur in the United States!

Clubtail Family (and Petaltail Family)

The eyes of clubtail dragonflies (and petaltails) are widely separated, somewhat similar to the eyes of damselflies. The Clubtail Family is the second largest family of dragonflies, so this field marker should be useful for identifying a lot of dragonflies to the family level — if only clubtails were as easy to identify down to the species level!

Ashy- or Lancet Clubtail dragonfly

09 MAY 2013 | Meadowood Recreation Area | Ashy/Lancet Clubtail (female)

The preceding dragonfly is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. But one look at those eyes and you know it’s definitely some species of clubtail!

Spiketail Family

Notice the eyes of the following dragonfly nearly touch at a point between its eyes — that’s a distinctive field marker for the Spiketail Family.

Brown Spiketail dragonfly (female)

09 MAY 2013 | Meadowood Recreation Area | Brown Spiketail (female)

Cruiser, Emerald, and Skimmer Families

In a few families of dragonflies, the eyes meet along a short seam near the face.

The Skimmer Family is the largest family of dragonflies. Many species of Skimmers are common and fairly easy to identify.

There are fewer species of dragonflies in the Cruiser Family than the Skimmer Family; no other dragonflies in the United States look similar to cruisers.

Stream Cruiser dragonfly (male)

02 MAY 2013 | Accotink Bay Wildlife Refuge | Stream Cruiser (male)

Many species of the Emerald Family feature distinctive bright green eyes, hence the family name.

Mocha Emerald dragonfly (Somatochlora linearis)

25 JUL 2012 | The Wildlife Sanctuary | Mocha Emerald (male)

Darner Family

The eyes of Darners meet along a long seam from front-to-back.

Common Green Darner dragonflies (mating pair, in tandem)

14 AUG 2012 | Huntley Meadows Park | Common Green Darner (mating pair)

Self-test

OK, let’s apply what you just learned. Looking at the eyes only, can you identify the family for the following dragonfly? If you would like to know whether your answer is correct, then please leave a comment.

Teacher’s Note: In order to avoid revealing the answer to the one-question quiz as soon as the first person comments, I changed the settings for this blog so that comments must be approved manually.

Common Sanddragon dragonfly (male)

26 JUN 2015 | Wickford Park | [Insert family name here.]

Editor’s Notes: This post is adapted from Dragonfly Head & Eyes, one of many excellent guides on the Odes for Beginners Web site. Thanks for the inspiration, Sheryl Chacon!

Copyright © 2015 Walter Sanford. All rights reserved.

Mochas gracias, amigos!

July 25, 2014

The following photographs show several male Mocha Emerald dragonflies (Somatochlora linearis) spotted along a small stream that flows through the forest at a remote location in Huntley Meadows Park. Mochas were my constant companions as I explored the habitat in search of more uncommon species of dragonflies, such as the Arrowhead Spiketail dragonfly I discovered on 07 July 2014.

It’s challenging to photograph perching Mochas Emeralds because they prefer shady spots; it’s more challenging to shoot them in flight. Mocha Emerald dragonflies patrol back-and-forth along the center of a stream, pausing to hover in place at times — be prepared to go for it when they hover nearby. Properly exposed photographs are practically impossible to capture: graininess is inevitable using relatively low ISOs and faster shutter speeds; a flash-equipped camera is essential.

All of the photos were shot using the following camera settings: RAW+JPEG; Auto exposure; Auto ISO, Limit Set (400); Auto white balance; Shutter priority; Flash On, Fired; Spot metering; AF Mode (1-area-focusing). Select EXIF information appears in the caption for each photo.

The first two photos were shot on 17 July 2014.

Mocha Emerald dragonfly (male, in flight)

ISO 400; 1/1000s; f/5.2; 108mm (600mm, 35mm equivalent)

Mocha Emerald dragonfly (male, in flight)

ISO 400; 1/1000s; f/5.2; 108mm (600mm, 35mm equivalent)

The last two photos were taken on 22 July 2014.

Mocha Emerald dragonfly (male, in flight)

ISO 400; 1/1000s; f/4.1; 57.2mm (318mm, 35mm equivalent)

Mocha Emerald dragonfly (male, in flight)

ISO 400; 1/1000s; f/4.1; 57.2mm (318mm, 35mm equivalent)

I prefer a shutter speed of 1/1,300s for stop-action photography of dragonflies in flight, although that shutter speed is a little too fast for low-light conditions and a little too slow to stop wing motion completely. See Dragonflies in Flight, a slideshow featuring 68 still photographs by Walter Sanford. (Hey, that’s me!)

Copyright © 2014 Walter Sanford. All rights reserved.

Mocha Emerald dragonflies: denizens of the dark

July 11, 2014

Mocha Emerald dragonflies (Somatochlora linearis) seem to prefer shady spots, unlike most odonates, so be sure to bring a flash-equipped camera when you hunt Mochas. And be sure to wear your Bug Shirt and Pants — mosquitos like shady spots too!

The following photographs feature two of several Mocha Emeralds spotted while I explored a small stream at a remote location in Huntley Meadows Park on 07 July 2014.

The first individual is a male, based upon its terminal appendages.

Emerald dragonfly, probably a Mocha Emerald (Somatochlora linearis)

Photo 1. Mocha Emerald dragonfly (male).

Photos 2 and 3 show another male Mocha, as indicated by its terminal appendages and the “indentations” on its hind wings (near the body).

Emerald dragonfly, probably a Mocha Emerald (Somatochlora linearis)

Photo 2. Mocha Emerald dragonfly (male).

Emerald dragonfly, probably a Mocha Emerald (Somatochlora linearis)

Photo 3. Mocha Emerald dragonfly (male).

Hind wing venation and shape can identify the sex of most dragonflies. Petaltails, darners (except Anax), clubtails, spiketails, cruisers, and some emeralds. With the striped emeralds (Somatochlora) the shape of the hind wing does differ between the sexes. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast.

Contrast the “indented” shape of a male Mocha hind wing (see Photo 3) with the rounded shape of a female Mocha hind wing, shown below.

Ed-Lam_Mocha-Emerald-dragonfly-female-hind-wing

Image showing rounded shape of female Mocha hind wing (near the body).

Editor’s Note: The preceding image used with permission from Ed Lam.

Copyright © 2014 Walter Sanford. All rights reserved.


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