Archive for the ‘Canon 580EX Speedlite’ Category

Mayfly (Hexagenia sp.)

June 15, 2017

A mayfly (Hexagenia sp.) was spotted near the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female subimago.

Editor’s Note: Special thanks to several members of the BugGuide Facebook group for help in identifying my unknown aquatic insect.

[This is] a female subimago. The males have larger eyes, and the opaqueness of the wings indicates that it is a subimago. Source Credit: Sharon Moorman, BugGuide Facebook group.

Copyright © 2017 Walter Sanford. All rights reserved.

Northern Watersnake

June 13, 2017

A Northern Watersnake (Nerodia sipedon sipedon) was spotted during a photowalk along Pope’s Head Creek at Hemlock Overlook Regional Park, Fairfax County, Virginia USA.

03 MAY 2017 | Fairfax County, VA | Northern Watersnake

Look closely at the full-size version of the following photo. Did you notice the fresh blood on the underside of its body? Also notice the scar on the dorsal side of the snake’s body. The former is probably blood from prey; the latter is probably the result of an attack by another predator.

03 MAY 2017 | Fairfax County, VA | Northern Watersnake

Copyright © 2017 Walter Sanford. All rights reserved.

Pop quiz answer key

June 9, 2017

Perhaps the simplest way to provide answers to the recent pop quiz — in which readers were challenged to identify the gender of two Southern Spreadwing damselflies (Lestes australis) — is to show what the teneral/immature male (shown in my last post) will look like when he’s a little older.

The following photos show Southern Spreadwings spotted at Mason Neck West Park, Fairfax County, Virginia USA. Both individuals are male, as indicated by their terminal appendages and blue coloration.

Both photographs of the male Southern Spreadwings were taken at an angle that shows their terminal appendages clearly.

All male damselflies have four terminal appendages, collectively called “claspers.” Male damselfly terminal appendages don’t look exactly the same for all species of damselflies, but their function is identical. Claspers are used to grab and hold female damselflies during mating: an upper pair of cerci (“superior appendages”) and a lower pair of paraprocts (“inferior appendages”).

In contrast, female damselflies have two cerci (sing. cercus), superior appendages that have little or no function. Notice the two “nubs” at the tip of the abdomen, as shown in the photo of the female Southern Spreadwing that was featured in the pop quiz.

Editor’s Notes: There are five families of damselflies (Suborder Zygoptera) in the United States of America, although only three families occur in the mid-Atlantic region: Family Calopterygidae (Broad-winged Damselflies)Family Coenagrionidae (Narrow-winged Damselflies); and Family Lestidae (Spreadwings).

Male Broad-winged Damselflies and Spreadwing Damselflies have terminal appendages that are large enough to see with the unaided eye. Generally speaking, both male and female Narrow-winged Damselflies are too small to see their terminal appendages clearly in most photographs.

Copyright © 2017 Walter Sanford. All rights reserved.

Pop quiz

June 7, 2017

OK, it’s time to assess what you’ve learned about damselflies by following my blog.

Two Southern Spreadwing damselflies (Lestes australis) were photographed on the same day at the same location. Both damselflies are teneral/immature, that is, they are relatively young. One is a female; one is a male. Can you identify the gender of the damselflies shown in the following photos?

I’ll give you a hint: Examine their terminal appendages by looking at the full-size version of both photos.

No. 1

No. 2

Editor’s Note: The answer key will be published in my next post.

Copyright © 2017 Walter Sanford. All rights reserved.

Pop goes the Cobra!

June 5, 2017

Good photographers strive to shoot photos that “pop,” rather than ones that are dull and flat. If you look at the full-size version of the following image, then I think you’ll agree with me — this photo pops!

Cobra Clubtail dragonfly (Gomphurus vastus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages.

Tech Tips: I carried two digital cameras during the trip to Riverbend Park: a Panasonic DMC-FZ150 superzoom bridge camera plus Canon 580EX Speedlite, my go-to kit for photowalking; as well as my Fujifilm X-T1Fujinon XF55-200mm zoom lens, and Fujifilm EF-X500 shoe mount flash. I’ve used the Panasonic camera for years and know to set the camera for optimal performance. In contrast, every time I picked up the Fujifilm camera I felt like I had no idea what I was doing!

Although I’ve owned the X-T1 for several years, I have used it mostly for studio photography. Now that Fujifilm has embraced high-speed sync flash photography, I plan to continue experimenting with using the X-T1 for wildlife photography. The X-T1 is a very capable camera — in time I hope to become as familiar with it as I am with my DMC-FZ150.

Copyright © 2017 Walter Sanford. All rights reserved.

Warming up

June 3, 2017

Faithful followers of my photoblog know I’m all about the odonates, that is, dragonflies and damselflies. But hey, I’m an equal opportunity wildlife photographer so when the ode-hunting starts slowly — as it did on this day — I like to “warm up” by shooting a few photos of anything that catches my eye.

03 MAY 2017 | Fairfax County, VA | Eastern Tiger Swallowtail (male)

Like this Eastern Tiger Swallowtail butterfly (Papilio glaucus) that was spotted along Pope’s Head Creek at Hemlock Overlook Regional Park, Fairfax County, Virginia USA. This individual is a male.

Copyright © 2017 Walter Sanford. All rights reserved.

If snakes could talk

June 1, 2017

In my experience, snakes flick their tongue frequently when they feel threatened by a predator. If snakes could talk, then this one might be saying “You’re making me feel anxious!”

10 MAY 2017 | Fairfax County, VA | Eastern Gartersnake

An Eastern Gartersnake (Thamnophis sirtalis sirtalis) was spotted along Pope’s Head Creek at Hemlock Overlook Regional Park, Fairfax County, Virginia USA. A wider view shows the snake is approximately two (2) feet in length. Notice its tail appears to have been amputated and healed afterward.

10 MAY 2017 | Fairfax County, VA | Eastern Gartersnake

A closer look at the snake shows several fresh injuries along the body, such as the gash near its head.

10 MAY 2017 | Fairfax County, VA | Eastern Gartersnake

Several bus loads of middle school students were visiting the park on 10 May 2017. I saw three students downstream from me who were separated from the larger group. They were throwing rocks at something along the shore. As I approached them, they started walking in the opposite direction. I spotted the snake when I reached the same place where the students had been throwing rocks.

10 MAY 2017 | Fairfax County, VA | Eastern Gartersnake

I’m guessing the students were trying to kill the snake before they saw me. So if snakes could talk, then this one might be saying “Thank you for saving my life!”

10 MAY 2017 | Fairfax County, VA | Eastern Gartersnake

Editor’s Comments: What’s the take-away from this ugly experience? This is another example of “good thought, bad idea.” It was a good thought to schedule a school field trip to a nature park; it was a bad idea to lose track of several students! Middle school students require adult supervision at all times. Trust me, as a retired K-12 science teacher, this is the voice of experience talking. The teachers are lucky none of their students were injured when they were missing in action. The snake wasn’t as fortunate — it was injured as a consequence of the teachers’ negligence. Let’s hope the snake survived its injuries!

Copyright © 2017 Walter Sanford. All rights reserved.

Swift River Cruiser (emergent female)

May 30, 2017

A Swift River Cruiser dragonfly (Macromia illinoiensis) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a late-stage emergent teneral female, as indicated by her terminal appendages.

Many of the major milestones during the miraculous process of emergence occurred before I spotted the dragonfly. I photographed the process from the first sighting to the time when I had to stop (see The Backstory, below): I shot 102 photos in approximately one hour; time is compressed by showcasing five (5) select photos from the first-to-last sighting.

The following photo is the first image from a time-series documenting the late-stage emergence of the teneral female. Elapsed time is expressed in hh:mm:ss format, e.g., 00:00:00 is the time when I spotted the emergent teneral female, and 01:01:15 is the total elapsed time.

27 MAY 2017 | 09:09:13 am EDT | Elapsed time: 00:00:00

The wings seem to be fully expanded (as shown in the preceding photo), evidenced by the fact that it appears some of the greenish hemolymph has been pumped out of the wings and into the abdomen.

27 MAY 2017 | 09:51:08 am EDT | Elapsed time: 00:41:55

Notice the wings are mostly clear in the following photo, in contrast with the first photo in this gallery. Next the abdomen expanded slowly until it was longer than the wings, as shown in the last photo.

27 MAY 2017 | 09:52:33 am EDT | Elapsed time: 00:43:20

As time passed, more of the adult coloration began to appear. Notice the large yellow spot on the dorsal side of abdominal segment seven (S7).

27 MAY 2017 | 09:57:39 am EDT | Elapsed time: 00:48:26

The last photo shows the dragonfly waiting for the wings and body to harden before its first flight.

27 MAY 2017 | 10:10:28 am EDT | Elapsed time: 01:01:15

The Backstory

I woke up at 4:30 a.m. in order to be at Riverbend Park when the gates open at 7 a.m. I had to attend a training session in order to be a volunteer collector of dragonfly exuviae for a research program sponsored by the park. The class started at 10 a.m., but I wanted to look around and shoot photos before the class.

I found almost nothing photo-worthy until soon after 9:00 a.m. when I spotted the emergent Swift River Cruiser dragonfly. The emergence was well underway at that point; I had to go to class before the wings spread and the teneral dragonfly flew away.

The emergence site was in a high-traffic location, so the daughter of a woman in the class guarded/watched the teneral until it flew away safely. After class, I collected the exuvia. I will shoot a set of studio macro photographs of the exuvia before returning the specimen to the park.

Swift River Cruiser is a new species of dragonfly for my life list.

Copyright © 2017 Walter Sanford. All rights reserved.

Crayfish

May 26, 2017

A crayfish was spotted in the shallows of Bull Run, under several inches of water. I estimate it was 3-4 in (~7.6-10.2 cm) in length.

Many crayfish can be particularly hard to identify from a photograph and many new species are still being discovered in Virginia’s waterways. This large crayfish is from the Family Cambaridae and is likely a native species. Other crayfish found in Northern Virginia, like the rusty crayfish (Orconectes rusticus) and red swamp crayfish (Procambarus clarkii), were likely introduced via the food industry and pose a serious threat to native crayfish populations. Source Credit: John Burke, Ecologist III, Stormwater Management Branch, Fairfax County Department of Public Works and Environmental Services.

10 MAY 2017 | Fairfax County, VA | crayfish (underwater)

Notice the first, second, and third pairs of walking legs feature chelae (plural).

A chela /kˈiːlə/, also named claw, nipper, or pincer, is a pincer-like organ terminating certain limbs of some arthropods. The name comes from Greek (χηλή) through New Latin (chela). The plural form is chelae. Legs bearing a chela are called chelipeds. Source Credit: Chela (organ), Wikipedia.

Also notice the slimy stuff on the rocks that makes them super slippery!

The slimy, slippery coating you find on rocks in aquatic systems is periphyton. In freshwater systems, periphyton is mostly comprised of algae but other microorganisms and detritus also collect on submerged rocks. Periphyton serves as an essential food source to many aquatic organisms and can also act as a bioindicator, signaling changes in water chemistry and nutrient levels in the system (Chetelat et al. 1997). Source Credit: John Burke.

Tech Tip:  My Canon 580EX Speedlite external flash unit was set for 1/16 power in order to penetrate the water and illuminate the subject on a bright, sunny day.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Hog-nosed Snake

May 24, 2017

The only downside — or upside, depending upon your point of view — to my new hotspot for hunting odonates is there are only two trails in/out and both paths are steeply-inclined. Going in, not so bad walking downhill; going out, not so much fun!

I stopped to catch my breath as I was walking up a long trail with a 45-degree slope. I heard a rustling sound in the vegetation on the left side of the trail, a little beyond where I was standing. I moved closer slowly until I spotted my first Eastern Hog-nosed Snake (Heterodon platirhinos)!

10 MAY 2017 | Fairfax County, VA | Eastern Hog-nosed Snake

Although the name for this snake is less than flattering, notice the distinctive orange fleur-de-lis shape on top of its head. The coloration of Eastern Hog-nosed Snake is variable; I was fortunate to see one of the more colorful ones.

10 MAY 2017 | Fairfax County, VA | Eastern Hog-nosed Snake

I never had a clear view of the entire snake, but I estimate it was two-to-three feet in length.

Copyright © 2017 Walter Sanford. All rights reserved.


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