Archive for the ‘Canon EOS XTi’ Category

Monarch butterfly chrysalises

February 7, 2017

Let’s continue the Monarch butterfly (Danaus plexippus) theme by flashing back to a time several years ago when my best camera for photowalking was either an Apple iPhone or whatever camera gear I could borrow.

Patuxent Research Refuge

A Monarch butterfly chrysalis was spotted on 02 September 2012 at the Patuxent Research Refuge, Laurel, Maryland USA. The chrysalis was attached to a telephone callbox outside the Visitor Contact Station, North Tract. The chrysalis was located near a bed of milkweed plants. I observed Monarch butterfly caterpillars (larvae) feeding on the same milkweed on 26 August 2012.

The next image is a closer crop of the preceding photo, taken using a loaner Canon EOS Rebel XTi DSLR camera.

Hollin Meadows Elementary School

A Monarch butterfly chrysalis casing was spotted during a photowalk on 09 October 2010 at the Children’s Garden at Hollin Meadows Science and Math Focus School, Fairfax County, Virginia USA. The chrysalis was attached to the outside of a classroom window near a planting of Scarlet milkweed (Asclepias curassavica).

I observed Monarch butterfly caterpillars (larvae) feeding on the Scarlet milkweed plants during late August through early September 2010. Sometime later, during the pupal stage of its life, one of the caterpillars created a chrysalis on a classroom window in order to transform from larva to adult. I discovered the empty casing after the adult Monarch butterfly had emerged from its chrysalis.

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

The photo was taken using an Apple iPhone 3GS and annotated using Adobe Photoshop.

Copyright © 2017 Walter Sanford. All rights reserved.

Maturation

August 1, 2015

Widow Skimmer dragonfly (Libellula luctuosa) was spotted during a photowalk around Mulligan Pond, Jackson Miles Abbott Wetland Refuge (JMAWR).

A Widow Skimmer dragonfly (Libellula luctuosa) spotted at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a mature male.

24 JUL 2015 | JMAWR | Widow Skimmer (mature male)

This individual is a mature male that has mated many times, as indicated by his coloration, terminal appendages, and scratches on the 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 midabdomen 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.

A Widow Skimmer dragonfly (Libellula luctuosa) spotted at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a mature male.

24 JUL 2015 | JMAWR | Widow Skimmer (mature male)

Contrast the appearance of the mature male Widow Skimmer with the following immature male, spotted at Huntley Meadows Park (HMP). Notice the mature male has two features that differentiate it from the immature male: white wing spots; and white pruinescence covering part of its thorax and all of its abdomen.

A Widow Skimmer dragonfly (Libellula luctuosa) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an immature male.

06 JUN 2015 | HMP | Widow Skimmer (immature male)

“Maturation,” the title of this post, also refers to my growth as an odonate hunter and photographer/photo editor. One look at the following photographs of the first Widow Skimmer I saw in the field, and it’s evident I’ve progressed to a higher level of dragonfly spotting during the past three years.

The preceding gallery features a male Widow Skimmer spotted at Lake Allen, Patuxent Research Refuge (North Tract). Admittedly not my best work, these photos were taken the first time I used a DSLR camera.

Copyright © 2015 Walter Sanford. All rights reserved.

Blues for “Bluets”

July 12, 2015

Regular readers of my photoblog know I love me some odonates! Mostly, that is. Many American Bluets, members of the Pond Damsels Family of damselflies, can be difficult to identify, especially in the field. There are many species of bluets, most of them are blue, and many of them look similar. Yes, sometimes I get the blues when trying to identify bluets — no wonder I lovingly refer to them as “damnselflies!”

Five species of bluets are listed on the Friends of Huntley Meadows Park Odonata species list of damselflies: Familiar Bluet (Enallagma civile); Big Bluet (Enallagma durum); Stream Bluet (Enallagma exsulans); Skimming Bluet (Enallagma geminatum); and Orange Bluet (Enallagma signatum).

Orange Bluets, named for their orange-and-black coloration, are easy to identify and relatively common in the central wetland area at the park.

The fact of the matter is you’re unlikely to see more than one or two of the blue bluets on the species list, so there should be no need to curse my little friends in frustration because you’re unable to identify them. Look closely at the pattern of blue-and-black markings on the abdomen of males and you should be able to easily differentiate the three species of bluets featured in this post. Identifying females can be a lot more challenging.

Familiar Bluet

In my experience, the only blue bluet you’re likely to see in the central wetland area at Huntley Meadows Park (HMP) is Familiar Bluet (Enallagma civile).

Familiar Bluet damselfly (male, in flight)

15 SEP 2014 | HMP | Familiar Bluet (male, in flight)

Stream Bluet

Stream Bluets (Enallagma exsulans) are relatively common along some of the streams that flow through Huntley Meadows Park, such as Barnyard Run.

A Stream Bluet damselfly (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

24 JUN 2015 | HMP | Stream Bluet (male)

It’s helpful to get shots of mating pairs in tandem, since males and females of the same species can look quite different.

A mating pair of Stream Bluet damselflies (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem.

10 JUL 2015 | HMP | Stream Bluets (mating pair, in tandem)

Female Stream Bluets are polymorphic, displaying either green or blue on the thorax. The green morph appears in the two photos of a mating pair of Stream Bluets featured in this post.

A mating pair of Stream Bluet damselflies (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem.

10 JUL 2015 | HMP | Stream Bluets (mating pair, in tandem)

Big Bluet

The author has never seen a Big Bluet damselfly (Enallagma durum) at Huntley Meadows Park. My theory is the wetlands at the park are the wrong habitat for Big Bluets.

Habitat Large sandy lakes and lower reaches of rivers, even extending into brackish estuaries. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 2156-2157). Princeton University Press. Kindle Edition.

It’s noteworthy that the only location where I have seen Big Bluets is Accotink Bay Wildlife Refuge (ABWR), and Ken Larsen’s photo of a Big Bluet (linked from the FoHMP Odonata species list) is from Occoquan Bay National Wildlife Refuge. Are you seeing the same pattern I see? The common keyword between our Big Bluet spottings is “bay.” Unless someone can show me a photograph of a Big Bluet spotted at Huntley Meadows Park, I feel strongly it should be deleted from the FoHMP Odonata species list.

A Big Bluet damselfly (Enallagma durum) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a male, shown eating an unknown insect.

17 SEP 2012 | ABWR | Big Bluet (male, eating prey)

The following poor quality photo is used to provide another illustration of the idea that it’s helpful to get shots of mating pairs in tandem, since males and females of the same species can look quite different. Female Big Bluets are polymorphic, displaying either brown or blue coloration. The brown morph is shown below.

A mating pair of Big Bluet damselflies (Enallagma durum) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This pair is in tandem.

10 SEP 2012 | ABWR | Big Bluet (mating pair, in tandem)

Related Resource: Dragonflies of Loudoun features a flight calendar for dragonflies and damselflies. Familiar Bluets are on the wing from July through September; Stream Bluets from May through August. Big Bluets aren’t listed. Hmmm, could it be because there aren’t any bays located in Loudoun County, Virginia?

Editor’s Note: The environment at Huntley Meadows Park may not be the ideal habitat for Skimming Bluet damselflies (Enallagma geminatum). The author has never seen a Skimming Bluet at the park, and the species isn’t linked from the FoHMP Odonata species list, suggesting Ken Larsen has never photographed one. If you have a photo of a Skimming Bluet at Huntley Meadows, then please contact me.

Copyright © 2015 Walter Sanford. All rights reserved.

Great Blue Skimmer dragonfly terminal appendages

April 3, 2015

I spotted an unknown dragonfly on 17 May 2012 and sent the following photo (without annotation) to Matt Ryan for his take on the identity of the dragonfly. Matt and I had taken the same introductory class on dragonflies during Summer 2011 at Huntley Meadows Park (HMP). Both of us were eager to learn more about odonates in order to move to the next level of dragonfly spotting.

Matt and I narrowed the field of possible identities to either Great Blue Skimmer (Libellula vibrans) or Slaty Skimmer (Libellula incesta), but we weren’t certain of its gender or age. As I recall, Matt was the first one to mention terminal appendages — a useful field marker that turned out to be one of the key characteristics that enabled us to correctly identify the specimen as an immature male Great Blue Skimmer.

And so it began — my interest in learning more about dragonfly terminal appendages led to lots of new discoveries and remains one of the go-to field markers I look for when identifying dragonflies.

Great Blue Skimmer dragonfly (immature male)

17 MAY 2012 | HMP | Great Blue Skimmer (immature male)

Immature males appear similar to immature females of the same species (and some mature females) for many types of dragonflies that display sexual dimorphism. This is true for many members of the Skimmer Family of dragonflies, such as Great Blue Skimmer. Terminal appendages may be used to differentiate gender for many species of dragonflies.

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16 AUG 2013 | ABWR | Great Blue Skimmer (mature male)

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”).

Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

A Great Blue Skimmer dragonfly (Libellula vibrans) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

12 SEP 2012 | ABWR | Great Blue Skimmer (mature female)

Look closely at the full-size version of the preceding image. Female Great Blue Skimmers have two flanges beneath their eighth abdominal segment (S8) that are used to scoop water when laying eggs (oviposition), hence the family name “Skimmer.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Related Resources: Odonate Terminal Appendages.

Editor’s Note: Matt Ryan went on to become a professional naturalist who works at Huntley Meadows Park. Matt is an excellent all-around naturalist; botany is Matt’s area of specialization.

Copyright © 2015 Walter Sanford. All rights reserved.

Great Blue Skimmer dragonfly (immature male)

April 11, 2014

Great Blue Skimmer dragonfly (immature male)

The preceding photograph shows a Great Blue Skimmer dragonfly (Libellula vibrans) spotted on 14 May 2013 during a photowalk at Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia USA.

This individual is an immature male, as indicated by its coloration and terminal appendages. Notice the immature male Great Blue Skimmer dragonfly resembles the female of the same species.

Males often go through an immature stage in which they are patterned much like females but then change dramatically at maturity by adding a layer of pruinosity (a powdery bloom much like the one we see on plums) to part or all of their thorax and abdomen. Most pruinosity is whitish to pale blue. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 696-698). Princeton University Press. Kindle Edition.

Copyright © 2014 Walter Sanford. All rights reserved.

Eastern Pondhawk dragonflies

May 14, 2013

The following slideshow features a couple of green Eastern Pondhawk dragonflies (Erythemis simplicicollis) spotted at two locations in Fairfax County, Virginia USA. Male Eastern Pondhawks are blue and females are green so these two dragonflies must be females, right? In a word, wrong.

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Do you see any difference between the two dragonflies? The dragonfly shown in Slide 1 is a mature female Eastern Pondhawk; Slide 2 shows an immature male. Look closely at the tip of the abdomen for both dragonflies: see a full-size version of Slide 1; and Slide 2. Notice the differences between male- and female terminal appendages, as shown in the following composite image: male appendages are shown in the background photo; female appendages are shown in the inset photo.

Eastern Pondhawk dragonfly (immature male)

Immature male (background photo) | Mature female (inset photo)

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”). Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

Adult Eastern Pondhawk dragonflies exhibit sexual dimorphism: mature males are covered by blue pruinescence; females are green. The male Eastern Pondhawk’s green face distinguishes it from other similar-looking blue dragonflies. The following specimen was spotted at Accotink Bay Wildlife Refuge.

Eastern Pondhawk dragonfly (male)

Some species of dragonflies do not exhibit sexual dimorphism. Terminal appendages may be used to differentiate males and females for many types of dragonflies, such as Stream Cruisers (Didymops transversa).

Related Resources: Odonate Terminal Appendages.

Copyright © 2013 Walter Sanford. All rights reserved.

Honorable Mention Photos of 2012 (Part 2)

January 2, 2013

The following gallery shows Part 2 of my “Honorable Mention Photos of 2012.” The photos are presented in chronological order. All of the photos were taken using either my Panasonic Lumix DMC-ZS150 superzoom camera (No. 1-7, 10) or a borrowed Canon EOS Digital Rebel XTi (No. 8-9). All photos were post-processed using Apple Aperture 3.

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Photo captions:

  1. Northern Flicker (male, chicks, nest), 02 June 2012
  2. Twelve-spotted Skimmer dragonfly (male), 09 July 2012
  3. Great Blue Skimmer dragonfly (female, in flight), 12 July 2012
  4. Needham’s Skimmer dragonflies (mating pair), 12 July 2012
  5. Blue Dasher dragonflies (mating pair), 16 July 2012
  6. Green Heron (predator-prey), 23 July 2012
  7. Blue Dasher dragonfly/owl wearing sunglasses (male), 14 August 2012
  8. Black Saddlebags dragonfly (male), 10 September 2012
  9. Blue-faced Meadowhawk dragonfly (male), 12 September 2012
  10. Blue-faced Meadowhawk dragonfly (male), 12 October 2012

Related Resources:

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Top 10 Photos of 2012 (Part 2)

December 30, 2012

The following gallery shows Part 2 of my “Top 10 Photos of 2012.” The photos are presented in chronological order. All of the photos were taken using either my Panasonic Lumix DMC-ZS150 superzoom camera (No. 1-3) or a borrowed Canon EOS Digital Rebel XTi (No. 4-5). All photos were post-processed using Apple Aperture 3. “Honorable Mention” photos (20) will be posted soon.

P1070984-rw2-ver5_apertureP1140708-rw2-ver4_apertureP1150212-rw2-_ver3_aperture36pt_944-cr2-ver4_aperture36pt_366-cr2-ver3_aperture

Photo captions:

  1. Great Spangled Fritillary butterfly (feeding on Purple Milkweed flowers), 17 May 2012
  2. Common Green Darner dragonflies (mating pair, in tandem), 14 August 2012
  3. Common Ribbonsnake, 21 August 2012
  4. Black Saddlebags dragonfly (male), 10 September 2012
  5. Common Buckeye butterfly (feeding on Wingstem flowers), 10 September 2012

Related Resources:

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com

Rambur’s Forktail damselfly (female)

November 16, 2012

The following photos show a Rambur’s Forktail damselfly (Ischnura ramburii) spotted along the shore of Accotink Bay. This individual is the orange-red heteromorph female.

Females orange-red, olive green, or may look like males. Source Credit: Wikipedia.

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Habitat: Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia USA.

Special thanks to Mr. Chris Hobson, Natural Areas Zoologist with the Virginia Natural Heritage Program, Virginia Department of Conservation and Recreation, for kindly allowing Project Noah spotter “Louisa” and me to tag along on one of his wildlife surveys!

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com

Suspension bridge crossing Accotink Creek

November 9, 2012

The following gallery features several photos of the suspension bridge that crosses Accotink Creek in Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia USA. The bridge is quite scenic but the wooden deck moves up and down and side-to-side when you walk across it — VERY UNNERVING!

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The preceding photo shows Louisa Civilla Craven, my good friend and photowalking buddy, shooting photographs looking upstream from the bridge; the following photo shows the view in the same direction.

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The last photo shows the view downstream from the bridge.

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Copyright © 2012 Walter Sanford. All rights reserved.


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