Posts Tagged ‘migratory’

House Finches

April 8, 2017

Sometime after I moved to a new apartment, I noticed some cute little reddish-brown birds that sing a cheerful song. I used the free Merlin Bird ID App to identify the bird based upon a few simple observations. Turns out my little friends are House Finches (Haemorhous mexicanus).

As time passed and months stretched into years, I realized the birds appeared in the spring, hung around all summer, and disappeared in the fall.

These newly established eastern populations have since become migratory, and now spend winters in the southern parts of the United States. Source Credit: BioKIDS.

05 APR 2017 | The Beacon of Groveton | House Finch (male)

These photos show two of several House Finches spotted recently near the top of the seven-story parking garage at the Beacon of Groveton, Fairfax County, Virginia USA. Both individuals are male, as indicated by their reddish coloration.

05 APR 2017 | The Beacon of Groveton | House Finch (male)

Copyright © 2017 Walter Sanford. All rights reserved.

Wandering Glider dragonfly (male)

December 14, 2016

Wandering Glider dragonfly (Pantala flavescens) was spotted at Mason Neck West Park (MNWP), Fairfax County, Virginia USA. This individual is a male. Wandering Gliders do not display sexual dimorphism; terminal appendages may be used to differentiate females and males.

A Wandering Glider dragonfly (Pantala flavescens) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

04 OCT 2016 | Mason Neck West Park | Wandering Glider (male)

I like the subtle beauty of the coloration/pattern of markings along the abdomen of Wandering Gliders.

A Wandering Glider dragonfly (Pantala flavescens) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

04 OCT 2016 | Mason Neck West Park | Wandering Glider (male)

This guy was very skittish! I spooked him when I backed up for a slightly wider view of the scene — usually that happens the other way around.

Copyright © 2016 Walter Sanford. All rights reserved.

Wandering Glider (terminal appendages)

October 2, 2016

Wandering Glider is one of at least five major species of dragonflies known to be migratory in North America. One field marker most migratory dragonflies have in common: broad hindwings.

The very broad hindwings represent an important adaptation for gliding, … Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11276-11277). Princeton University Press. Kindle Edition.

Dragonflies are classified as either “fliers” or “perchers,” based upon their feeding habits. Wandering Gliders are fliers; it is uncommon to see fliers perching.

The following gallery of annotated photographs shows two Wandering Glider dragonflies (Pantala flavescens) spotted at Mason Neck West Park, Fairfax County, Virginia USA: one is a female; the other a male. Wandering Gliders do not display sexual dimorphism; terminal appendages may be used to differentiate females and males.

Female

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

A Wandering Glider dragonfly (Pantala flavescens) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a female.

27 SEP 2016 | Mason Neck West Park | Wandering Glider (female)

(See a full-size version of the original photo, without annotation. Aesthetically speaking, I prefer the subtle difference in composition of a similar photo that doesn’t show the cerci as well as the featured image.)

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”).

A Wandering Glider dragonfly (Pantala flavescens) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

27 SEP 2016 | Mason Neck West Park | Wandering Glider (male)

(See a full-size version of the original photo, without annotation. A similar photo with an obstructed view of the dragonfly’s wings provides a slightly closer look at the body.)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Pantala | Pantala flavescens | Wandering Glider | female | top view
  • Genus Pantala | Pantala flavescens | Wandering Glider | female | side view
  • Genus Pantala | Pantala flavescens | Wandering Glider | male | top view
  • Genus Pantala | Pantala flavescens | Wandering Glider | male | side view

See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Wandering Glider, provided by the Migratory Dragonfly Partnership.

Copyright © 2016 Walter Sanford. All rights reserved.

Black Saddlebags dragonfly (male)

August 23, 2015

A Black Saddlebags dragonfly (Tramea lacerata) was spotted in the hemi-marsh at Huntley Meadows Park. This individual is a male, as indicated by its coloration and terminal appendages.

A Black Saddlebags dragonfly (Tramea lacerata) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

05 JUL 2015 | Huntley Meadows Park | Black Saddlebags (male)

It is uncommon to see the broad-winged skimmers from the genus Tramea perching. Dragonflies are classified as either “fliers” or “perchers,” based upon their feeding habits. Black Saddlebags are fliers.

A Black Saddlebags dragonfly (Tramea lacerata) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

05 JUL 2015 | Huntley Meadows Park | Black Saddlebags (male)

Black Saddlebags is one of at least five major species of dragonflies known to be migratory in North America. Broad hindwings is an adaptation that enables Black Saddlebags to glide easily when flying. Dragonflies expend less energy when gliding, an aide to long-distance migration. According to the axiom in biology/morphology, form follows function.

Slaty Skimmer dragonflies (Libellula incesta), such as the mature male shown below, look somewhat similar to Black Saddlebags. Slaty Skimmers are “perchers.” Slaty Skimmers aren’t migratory; notice their hindwings are narrower than Black Saddlebags.

Related Resource: A sampler of male dragonfly claspers (Part 2). (See “Skimmer Family,” Black Saddlebags dragonfly.)

Copyright © 2015 Walter Sanford. All rights reserved.

Common Green Darner dragonfly (female)

November 6, 2014

A Common Green Darner dragonfly (Anax junius) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

The preceding Common Green Darner dragonfly (Anax junius) was spotted on 20 October 2014, perching briefly near a vernal pool in the forest at Huntley Meadows Park. This individual is a female.

Common Green Darner is one of at least five major species of dragonflies known to be migratory in North America. See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Common Green Darner, provided by the Migratory Dragonfly Partnership.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Anax | Anax junius | Common Green Darner | female | top view
  • Genus Anax | Anax junius | Common Green Darner | female | side view

Copyright © 2014 Walter Sanford. All rights reserved.

Swarm!

October 9, 2014

On 06 October 2014, I spotted what I would call a small swarm of Common Green Darner dragonflies (Anax junius) at a vernal pool in the forest at Huntley Meadows Park. There were at least 25-30 individuals, maybe more. They alternated between hawking flying insects, then perching/resting briefly in vegetation near the ground. The activity lasted all day, until dusk. I’m guessing the swarm stopped to refuel at the park while migrating southward.

Common Green Darner dragonfly (male)

The dragonfly shown in the preceding photo is a male, as indicated by its blue abdomen and terminal appendages.

Common Green Darner is one of at least five major species of dragonflies known to be migratory in North America. See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Common Green Darner, provided by the Migratory Dragonfly Partnership.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Anax | Anax junius | Common Green Darner | male | top view
  • Genus Anax | Anax junius | Common Green Darner | male | side view

Editor’s Note: Small swarms of Common Green Darner dragonflies were reported recently by spotters in other parts of Huntley Meadows Park.

Copyright © 2014 Walter Sanford. All rights reserved.

Wandering Glider dragonfly (male)

September 25, 2014

The following photographs show a Wandering Glider dragonfly (Pantala flavescens) spotted near the end of the boardwalk at Huntley Meadows Park on 23 September 2014. This individual is a male, based upon the following description.

Male: Eyes reddish; face orange. Thorax and abdomen yellow, upper part of abdomen orange. Darker orange median line on abdomen, expanded on each segment and forming black spots toward rear, on S8–10. Cerci black, obviously pale at base. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11282-11283). Princeton University Press. Kindle Edition.

Remember that “S8-10″ refers to abdominal segments eight through 10 (of 10), numbered from front to back.

It is uncommon to see the broad-winged skimmers from the genus Pantala perching. Dragonflies are classified as either “fliers” or “perchers,” based upon their feeding habits. Wandering Gliders are fliers. I was fortunate to be able to “work the shot” when this guy landed for a long rest during the afternoon!

Wandering Glider dragonfly (male)

Wandering Glider dragonfly (male)

Wandering Glider dragonfly (male)

Wandering Glider dragonfly (male)

Wandering Glider dragonfly (male)

Wandering Glider dragonfly (male)

Wandering Glider is one of at least five major species of dragonflies known to be migratory in North America. One field marker most migratory dragonflies have in common: broad hindwings.

The very broad hindwings represent an important adaptation for gliding, … Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11276-11277). Princeton University Press. Kindle Edition.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Pantala | Pantala flavescens | Wandering Glider | male | top view
  • Genus Pantala | Pantala flavescens | Wandering Glider | male | side view
  • Genus Pantala | Pantala flavescens | Wandering Glider | female | top view
  • Genus Pantala | Pantala flavescens | Wandering Glider | female | side view

See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Wandering Glider, provided by the Migratory Dragonfly Partnership.

Copyright © 2014 Walter Sanford. All rights reserved.

Common Green Darner dragonflies (mating pair)

July 29, 2014

The following photos show a mating pair of Common Green Darner dragonflies (Anax junius) spotted during a photowalk through the central wetland area at Huntley Meadows Park. This pair is “in tandem”: The male is shown on the right; the female on the left. The female is laying eggs on the surface of underwater plants (epiphytic ovipostion). The Common Green Darner dragonfly is the only North American darner that usually oviposits in tandem.

Common Green Darner dragonflies (mating pair, in tandem)

Common Green Darner is one of at least five major species of dragonflies known to be migratory in North America. See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Common Green Darner, provided by the Migratory Dragonfly Partnership.

Common Green Darner dragonflies (mating pair, in tandem)

Migratory Common Green Darner is one of the first species of dragonflies you are likely to see at Huntley Meadows during early spring, usually sometime in mid- to late-March. There is also a local population of Common Green Darners; the offspring of this mating pair will emerge from the hemi-marsh sometime next year.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Anax | Anax junius | Common Green Darner | male | top view
  • Genus Anax | Anax junius | Common Green Darner | male | side view
  • Genus Anax | Anax junius | Common Green Darner | female | top view
  • Genus Anax | Anax junius | Common Green Darner | female | side view

Copyright © 2014 Walter Sanford. All rights reserved.

Black Saddlebags dragonflies (males, in flight)

July 27, 2014

The following photographs show two Black Saddlebags dragonflies (Tramea lacerata) spotted in flight over the central wetland area at Huntley Meadows Park on 25 July 2014.

Both individuals are males, as indicated by the hamules that are visible below the second segment of their abdomen. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back. Digital Dragonflies features a side view of a male Black Saddlebags in which the hamules are shown clearly.

Black Saddlebags dragonfly (male, in flight)

Black Saddlebags is one of at least five major species of dragonflies known to be migratory in North America. See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Black Saddlebags, provided by the Migratory Dragonfly Partnership.

Black Saddlebags dragonfly (male, in flight)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Tramea | Tramea lacerata | Black Saddlebags | male | top view
  • Genus Tramea | Tramea lacerata | Black Saddlebags | male | side view
  • Genus Tramea | Tramea lacerata | Black Saddlebags | female | top view
  • Genus Tramea | Tramea lacerata | Black Saddlebags | female | side view

Copyright © 2014 Walter Sanford. All rights reserved.

Down at The BoG

July 17, 2014

I live in a “luxury apartment” building called The Beacon of Groveton. Many residents of the building refer to the place as “The BoG.” Turns out the nickname is both an acronym as well as a word that describes the habitat accurately — believe me when I tell you there’s a lot of lipstick on this luxurious pig! (Hey, don’t take my word — go to Yelp and search “Beacon of Groveton” for independent verification.)

By now you may be wondering, “Why don’t you move?” Did I mention The BoG is within walking distance of the hemi-marsh at Huntley Meadows Park?

OK, I admit that was a long way to go in order to explain the clever title of this post! I noticed a Spot-winged Glider dragonfly (Pantala hymenaea) perching on a red brick sidewalk outside The BoG when I returned home from an errand on 15 July 2014. The dragonfly looked dead; it was alive, albeit motionless. The Spot-winged Glider was still on the sidewalk by the time I returned with a camera; I was able to snap a few shots before it flew away. Down, not out!

The dragonfly’s apparent misfortune was my good fortune. It is uncommon to see the broad-winged skimmers from the genus Pantala perching. Dragonflies are classified as either “fliers” or “perchers,” based upon their feeding habits. Spot-winged Gliders are fliers.

Spot-winged Glider dragonfly (Pantala hymenaea)

Spot-winged Glider is one of at least five major species of dragonflies known to be migratory in North America. One field marker most migratory dragonflies have in common: broad hindwings.

The very broad hindwings represent an important adaptation for gliding, … Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11276-11277). Princeton University Press. Kindle Edition.

Spot-winged Glider dragonfly (Pantala hymenaea)

This individual is a female, as indicated by its coloration and terminal appendages. Thanks to Ed Lam, author and illustrator of Damselflies of the Northeast, for verifying my tentative identification of the dragonfly’s gender.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Pantala | Pantala hymenaea | Spot-winged Glider | female | top view
  • Genus Pantala | Pantala hymenaea | Spot-winged Glider | female | side view
  • Genus Pantala | Pantala hymenaea | Spot-winged Glider | male | top view
  • Genus Pantala | Pantala hymenaea | Spot-winged Glider | male | side view

See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Spot-winged Glider, provided by the Migratory Dragonfly Partnership.

Copyright © 2014 Walter Sanford. All rights reserved.


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