Archive for the ‘education’ Category

Gray Petaltail dragonfly (male)

May 29, 2019

Several Gray Petaltail dragonflies (Tachopteryx thoreyi) were observed during a photowalk with my good friend Mike Powell along a small forest stream at an undisclosed location in Prince William County, Virginia USA.

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

This individual — spotted in a sunny clearing — is a male, as indicated by his “indented” hind wings, and terminal appendages.

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

Both of the photos featured in this blog post are uncropped, that is, full resolution for the Panasonic Lumix DMC-FZ300 superzoom bridge camera (4,000 x 3,000 pixels). Needless to say, I was fairly close to this cooperative subject!

Copyright © 2019 Walter Sanford. All rights reserved.

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DMC-FZ150 versus DMC-FZ300

May 8, 2019

For years, my go-to camera kit for photowalking has been the Panasonic Lumix DMC-FZ150 superzoom digital camera and a Canon 580EX Speedlite. A formula of camera and flash settings that I call “set it and forget it” works most of the time, enabling me to focus on the subject rather than futzing around with camera/flash settings.

My new Panasonic Lumix DMC-FZ300 features some significant upgrades over the DMC-FZ150 such as a touch-screen LCD, built-in WiFi (enabling remote control of the camera using the “Panasonic Image App“), 49 focus points, 4K video, and an intriguing new feature that Panasonic calls “Post Focus.”

The two cameras are similar, but as I say often, similar is not the same. As appealing as the new features of the FZ300 are, the newer camera doesn’t perform like my older FZ150. After limited testing in both the studio and in the field, I have yet to find the new formula for “set it and forget it” using the FZ300. Disappointed and frustrated, I am!

Panasonic Lumix DMC-FZ150

A Springtime Darner dragonfly (Basiaeschna janata) was spotted along Popes Head Creek at Hemlock Overlook Regional Park, Fairfax County, Virginia USA. This individual is a male.

108mm (600mm, 35mm equivalent) | ISO 100 | f/5.2 | 1/800 s | -1 ev

Flash fired, in compulsory flash mode. My external flash unit is set for Manual mode at a power ratio of 1/16, plus or minus one stop. The other settings listed in the photo caption are typical of what I call “set it and forget it,” that is, these settings work for most subjects in most lighting conditions.

The preceding photo was included in my “Top 10 Photos of 2018.” Many, if not most, of the photos in this gallery were taken using the DMC-FZ150 and my “set it and forget it” formula.

Panasonic Lumix DMC-FZ300

A Brown Spiketail dragonfly (Cordulegaster bilineata) was spotted at Occoquan Regional Park, Fairfax County, Virginia USA. This individual is a male.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 1 ev

Flash fired, in compulsory flash mode.

A Common Green Darner dragonfly (Anax junius) was spotted at the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA. This individual is a female.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 0 ev

Flash fired, in compulsory flash mode.

A Harlequin Darner dragonfly (Gomphaeschna furcillata) was spotted at the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA. This individual is a female.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 0 ev

Flash fired, in compulsory flash mode.

What are the take-aways?

I prefer shooting in Shutter Priority mode at relatively fast shutter speeds (using the reciprocal rule) in order to reduce camera shake at longer focal lengths. If the ISO is set for 100 then the exposure triangle tells us that the only variable is aperture (f/stop). Using my “set it and forget it” formula of settings, the FZ150 typically opts for an f/stop of f/5.6 or higher (that is, a smaller lens opening); for some reason the FZ300 always seems to opt for f/2.8.

Problem is, there is too little depth of field at f/2.8! The only way I’m able to shoot serviceable photos using the FZ300 is to compose photos so the entire subject is nearly parallel to the focal plane and to sharpen the images using Adobe Photoshop.

I’m planning to start shooting in Manual mode so that I can set the ISO, aperture, and shutter speed. During limited testing in the studio, it was necessary to use a higher flash power ratio in order to get good exposure. Otherwise, Manual mode is the ultimate in “set it and forget it!”

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

Brown Spiketail dragonflies

May 6, 2019

Several Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted during a photowalk with my good friend Mike Powell at Occoquan Regional Park, Fairfax County, Virginia USA.

Male

The first individual is a male, as indicated by his “indented” hind wings, and terminal appendages. Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following photo.

The next individual is also male, as indicated by his hamules, located below abdominal segments two and three (S2 and S3).

Female

The last individual is a female, as indicated by her rounded hind wings and terminal appendages.

Credits

Thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for confirming my tentative identification of the gender of the first and last individuals.

Phenology

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).

Brown Spiketail is an “Early Season” species for locations in the Commonwealth of Virginia. I have noticed that the adult flight period for a given species of odonate in Northern Virginia tends to lag behind Amherst County, where my good friend Mike Boatwright (Mike B) lives, by about one-to-two weeks. When Mike B reported his first sighting of Brown Spiketail on 24 April in Amherst County, I knew it wouldn’t be long until Brown Spiketail would be flying in Fairfax County. Eight (8) days later, Mike Powell and I spotted our first-of-season Brown Spiketail dragonflies. Thanks for the heads-up, Mike B!

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

Battery Economics 101

April 22, 2019

I bought a package of eight (8) Energizer Ultimate Lithium AA batteries for $13.28 at Loew’s (hardware store) recently. Assuming that’s a typical price point — and it may not be since retail stores are well known for inflating the price of “impulse buy” items placed near the checkout stands — I wondered which type of battery is the better value, primary cells (like the Energizers) or secondary cells (i.e., rechargeable batteries)?

B&H Photo sells an 8-Pack of Panasonic eneloop pro AA Rechargeable NiMH Batteries (1.2V, 2550mAh) for $32.99.

At face value, rechargeable batteries cost ~2.5x more than primary cells. But the secondary cells are rechargeable up to 500 times! In other words, the consumer will recover the extra cost of secondary cells after recharging them only a few times.

External flash units can be real Energy Hogs, especially when shooting at higher flash ratios. So a word to the wise consumer, get a set of rechargeable batteries — they’re worth the extra cost.

Post Addendum

My good friend Mike Powell suggested this blog post should be updated to mention that rechargeable batteries require a charger. I recommend the following combo deal available from B&H Photo: Panasonic Eneloop Pro Rechargeable AA Ni-MH Batteries with Charger (2550mAh, Pack of Four) that sells for $26.30. Done!

Copyright © 2019 Walter Sanford. All rights reserved.

Uhler’s Sundragon (female)

April 19, 2019

A Uhler’s Sundragon (Helocordulia uhleri) was spotted during a photowalk along a mid-size stream at an undisclosed location in Northern Virginia USA.

This individual is a female, as indicated by her rounded hind wings and terminal appendages. All female dragonflies have a pair of cerci (superior appendages) that have little or no function. Both cerci are visible clearly in the full-size version of the following photo.

16 APR 2019 | Northern Virginia | Uhler’s Sundragon (female)

Notice the right hind wing is slightly malformed. It appears the wing failed to inflate completely during emergence. The malformation didn’t impair her ability to fly. Pollen (probably tree pollen) is especially noticeable on the darker parts of the body.

Just the facts, ma’am.

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 H. uhleri is 29 March to 27 June. The species is classified as common. Its habitat is “streams.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for H. uhleri seems to be longer than it is in reality. The adult flight period for a single site is probably no more than a month, and more likely around two-to-three weeks. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Uhler’s is 11 April to 05 May.

It’s also worth noting that the window of opportunity to see Uhler’s Sundragon closes rapidly after trees are in full leaf.

Is Uhler’s Sundragon common? I guess the answer to that question depends upon where you live. In Northern Virginia, Kevin Munroe classified H. uhleri as “rare.” In fact, I’m aware of only one location in Northern Virginia where Uhler’s Sundragon can be found with reasonable certainty.

Copyright © 2019 Walter Sanford. All rights reserved.

Great Blue Skimmer dragonfly (mature male)

April 12, 2019

Great Blue Skimmer dragonfly (Libellula vibrans) was spotted near a vernal pool in the forest at Huntley Meadows Park (HMP), Fairfax County, Virginia USA. This individual is a mature male, as indicated by his terminal appendages, discolored abdomen, and tattered wings.

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.

Copyright © 2019 Walter Sanford. All rights reserved.

So close, yet so far!

April 10, 2019

Two Common Whitetail dragonflies (Plathemis lydia) were spotted perching on a wooden fence rail located near the terminus of the Hike-Bike Trail at Huntley Meadows Park (HMP), Fairfax County, Virginia USA.

The individual shown on the left is a mature female; the one on the right is a mature male.

15 SEP 2016 | HMP | Common Whitetail (mature female and male)

Sexing Common Whitetail dragonflies

For many of the common species of odonates found in Northern Virginia, I created a collection of annotated guides that illustrates how to differentiate gender by looking at terminal appendages. The difference in the pattern of wings spots for male and female Common Whitetails is sufficient to identify gender.

Life Cycle of Odonates

Odonates (dragonflies and damselflies) are aquatic insects that spend most of their life as larvae that live in water; this stage of their life cycle can last from a few months to a few years, depending upon the species. Finally, they emerge from the water and metamorphose into adults in order to reproduce; their offspring return to the water and the cycle begins again.

I wonder how these two mature adults were able to be so close yet resist the compelling biological urge to hook up!

Copyright © 2019 Walter Sanford. All rights reserved.

Odonate calendars: VA Flight Dates

March 31, 2019

Google Calendar was used to synthesize “CHECKLIST OF THE DRAGONFLIES AND DAMSELFLIES OF VIRGINIA, April 2017 update” — Dr. Steve Roble’s excellent datasets for the Commonwealth of Virginia — into two calendars: Dragonflies (VA Flight Dates); and Damselflies (VA Flight Dates).

The Google Calendar default color palettes were used to color-code both calendars: Dragonflies is Graphite; and Damselflies is Birch. Individual events on each calendar are also color-coded by family.

Dragonflies

Here’s the way the dragonflies calendar looks using the Chrome Web browser on my Apple iMac desktop computer. Notice the Graphite colored vertical bar to the left of each event that indicates it belongs to the dragonflies calendar.

And here’s the way the dragonflies calendar looks using the free Google Calendar app on my Apple iPad mini 2.

Every event features the following information: common name; scientific name; early-date/late-date; abundance; and habitat.

New for 2019

An interactive version of both calendars is available online. The dragonflies calendar is shown below.

Regrettably, the color-coding is lost in the online, interactive version of both calendars. That is, unless you print the calendar.

Color-coding is also lost when the calendar is exported as an “.ics” file. That’s the bad news. The good news is the calendar can be edited after it is imported into Google Calendar and it’s easy to edit the entries to color-code them any way you like.

The colors of the rainbow (ROYGBIV) were used to color-code the seven families of dragonflies; the equivalent colors in the Google Calendar default color palette are shown in brackets.

  • R = Family Aeshnidae (Darners) [Tomato]
  • O = Family Cordulegastridae (Spiketails) [Tangerine]
  • G = Family Corduliidae (Emeralds) [Basil]
  • Y = Family Gomphidae (Clubtails) [Banana]
  • B = Family Libellulidae (Skimmers) [Peacock]
  • I = Family Macromiidae (Cruisers) [Blueberry]
  • V = Family Petaluridae (Petaltails) [Grape]

The colors for Emeralds and Clubtails were flip-flopped because it just makes sense the Emeralds should be color-coded green!

Damselflies

Here’s the way the damselflies calendar looks using the free Google Calendar app on my Apple iPad mini 2.

Like the dragonflies calendar, every event features the following information: common name; scientific name; early-date/late-date; abundance; and habitat.

“FSL” was used to color-code the three families of damselflies common to the mid-Atlantic states (USA); the equivalent colors in the Google Calendar default color palette are shown in brackets.

  • F – Family Calopterygidae (Broad-winged Damselflies) [Flamingo (formerly Tomato)]
  • S – Family Coenagrionidae (Narrow-winged Damselflies) [Sage (formerly Peacock)]
  • L – Family Lestidae (Spreadwings) [Lavendar (formerly Basil)]

For what it’s worth, all of the colors for the damselflies calendar are pastel shades.

New for 2019

An interactive version of the damselflies calendars is available online, as shown below.

Dragonflies and Damselflies

The damselflies calendar was updated for 2019 so that no colors are duplicated from the dragonflies calendar. This should help to eliminate confusion when both calendars are displayed at the same time, as shown below.

Lessons Learned

As I worked on the calendar, patterns began to emerge that I hadn’t noticed before. For example, it’s clear that the serious odonate hunter needs to hit the ground running as soon as early March. Remember that Dr. Roble’s dataset is for the entire state. You may not see a given species on its early-date, but it could be seen on that date and certainly can’t be seen if you don’t look!

Tech Tips

Download the “.ics” file from the Virginia Odonata Facebook group. Launch Google Calendar on a desktop computer. Create a new calendar by clicking on the three vertical dots to the right of “Add calendar” and selecting “Create new calendar”; give the calendar a name such as “Test Calendar” and click on the “Create calendar” button. (You can change the name later.) “Test Calendar” should appear in the list of calendars under “My calendars.”

Mouse-over the name “Test Calendar” and click on the vertical column of three dots, labeled “Options for Test Calendar” then select “Settings and sharing.” In the upper-left sidebar, click on “Import and export”; select the “.ics” file to import and select “Test Calendar” from the drop-down menu labeled “Add to calendar.” There are 143 events in the Dragonflies calendar; 56 events in the Damselflies calendar.

If you decide to color-code individual events like I did, click on an event then click on the pencil icon labeled “Edit event.” Select a color and click the “Save” button, then click the radio button for “All events.” Beware: You can right-click on an individual event and change its color but DON’T GO THERE! That results in an event that doesn’t occur annually using the new color you chose.

Related Resources

Kevin Munroe, former manager of Huntley Meadows Park, created an excellent calendar called Dragonflies of Northern Virginia – Flight Periods. This calendar is a valuable resource for hunting dragonflies in Northern Virginia. I think the value of Kevin Munroe’s calendar is enhanced by using it in combination with my visualization of Steve Roble’s dataset.

Dragonflies & Damselflies of Loudoun County features a flight calendar for dragonflies and damselflies.

Copyright © 2019 Walter Sanford. All rights reserved.

Powdered Dancer damselfly (female)

March 29, 2019

A Powdered Dancer damselfly (Argia moesta) was spotted during a photowalk along a small stream at Hemlock Overlook Regional Park, Fairfax County, Virginia USA.

This individual is a female, as indicated by her coloration. Female Powdered Dancers are polymorphic: this is the tan morph; there is also a blue morph that looks somewhat similar to males of the same species.

10 MAY 2017 | HORP | Powdered Dancer (female)

Also notice the female’s abdomen is thicker near the tip than the tip of a male’s abdomen, due to female egg-laying anatomy.

Credits

Sincere thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for help in identifying this specimen. My tentative identification, recorded in field notes dated 10 May 2017, proved to be incorrect.

I’m comfortable identifying some members of two of the three families of damselflies that occur in the mid-Atlantic states (USA), including Family Calopterygidae (Broad-winged Damselflies) and Family Lestidae (Spreadwings). Most members of the Family Coenagrionidae (Narrow-winged Damselflies), not so much.

I remember clearly the time when I was learning to identify dragonflies. I was more than a little confused at first. With persistence, the puzzle pieces started to fall into place sooner than I expected. Same story when I started learning to identify odonate exuviae. Never happened with damselflies, for whatever reason.

Copyright © 2019 Walter Sanford. All rights reserved.

Blue-fronted Dancers (male, female)

March 22, 2019

Male

A Blue-fronted Dancer damselfly (Argia apicalis) was spotted near Mulligan Pond at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA.

This individual is a male, as indicated by the pattern of blue coloration on his thorax and abdomen, plus the blue coloration on abdominal segments eight through 10 (S8-10).

25 SEP 2016 | Jackson Miles Abbott WR | Blue-fronted Dancer (male)

Female

Several Blue-fronted Dancers were spotted during a photowalk along Accotink Creek/Great Blue Heron Trail at Accotink Bay Wildlife Refuge (ABWR), Fairfax County, Virginia USA.

The first individual is a female, as indicated by two field marks.

Eyes brown, darker above; lack of blue in eyes in andromorph good distinction from male. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 3451-3452). Princeton University Press. Kindle Edition.

Female Blue-fronted Dancers are polymorphicandromorph females are blue like males; heteromorph females are brown-green. Andromorph females tend to be a lighter shade of blue than males of the same species.

This individual is a blue andromorph. Regardless of the color morph…

females never have blue on the last abdominal segments (S8-10). Source Credit: Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group.

02 AUG 2016 | ABWR | Blue-fronted Dancer (female)

More males

Two male Blue-fronted Dancers were spotted at Accotink Bay Wildlife Refuge.

02 AUG 2016 | ABWR | Blue-fronted Dancer (male)

02 AUG 2016 | ABWR | Blue-fronted Dancer (male)

Copyright © 2019 Walter Sanford. All rights reserved.


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