Posts Tagged ‘09NOV2017’

Thermal energy vampire!

November 24, 2017

The following photographs show an Autumn Meadowhawk dragonfly (Sympetrum vicinum) perching on Walter Sanford (hey, that’s me!) at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is a male, as indicated by his terminal appendages.

All three photos were taken by Lisa Young during a photowalk with me along Easy Road.

Most dragonflies are skittish. Some species of dragonflies are “friendly,” such as Blue Corporal dragonflies (Ladona deplanata) and Autumn Meadowhawk dragonflies (Sympetrum vicinum). It’s probably not a coincidence that both types of dragonflies are early- and late-season species, when the ambient air temperature is cooler.

Some odonate experts speculate dragonflies perch on people in order to absorb thermal energy radiated by the relatively warm human body. Or in this case, a black backpack — a good spot since darker-colored objects absorb and re-radiate thermal energy more quickly than lighter-colored objects.

Related Resource: Five Guys, a blog post by Walter Sanford featuring photos of male Autumn Meadowhawk dragonflies taken before the meet-up with Liza Young.

Copyright © 2017 Walter Sanford. All rights reserved.

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Eastern Gartersnake

November 18, 2017

An Eastern Gartersnake (Thamnophis sirtalis sirtalis) was spotted during a photowalk along Easy Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

After taking a closer shot of the snake’s head (above), I backed away for a wider view that shows the snake is a little more than two (2) feet in length (below).

Eastern Gartersnakes can be differentiated from Common Ribbonsnakes (Thamnophis sauritus sauritus) by the presence of “dark vertical lines on the supralabial scales.” This key characteristic is shown clearly in the following photo.

Copyright © 2017 Walter Sanford. All rights reserved.

Five Guys

November 16, 2017

Several Autumn Meadowhawk dragonflies (Sympetrum vicinum) were spotted along Easy Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. All of these individuals are male, as indicated by their terminal appendages.

Did you notice the preceding male appears to be missing his right hind wing? Perhaps I should rename this blog post “4.75 Guys.”

Editor’s Note: The photos in this gallery were taken a day before the first hard freeze in Northern Virginia that occurred overnight on Friday-Saturday, November 10-11. It will be interesting to see how many Autumn Meadowhawk dragonflies survived the record-setting low temperatures in the mid- to upper 20s.

Copyright © 2017 Walter Sanford. All rights reserved.

The Road Taken

November 14, 2017

Two ruts converged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth…

With sincere apologies to Robert Frost for slight modification of the title and first stanza of his famous poem The Road Not Taken in order to convey my impressions of Fall 2017 at Occoquan Bay National Wildlife Refuge.

Tech Tip: I used my Panasonic Lumix DMC-FZ150 superzoom camera to shoot the landscape photo featured in this blog post. The camera was set for manual focus at the hyperfocal distance for an aperture of f/4, based upon the instructions provided in the excellent video tutorial by Graham Houghton, “Panasonic Lumix FZ camera easier manual focus method — super point-and-shoot tip.”

Copyright © 2017 Walter Sanford. All rights reserved.

Confused by mild fall weather

November 12, 2017

A frog-let/toad-let — my term for small frogs and toads — was spotted during a photowalk along Easy Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. Turns out it’s a Spring Peeper (Pseudacris crucifer), as indicated by the dark “X” on the frog’s dorsal side.

Every spring, the sound of male Spring Peepers calling for mates is deafening. You hear them, but you see them rarely. You don’t expect to see them during the second week in November!

Some amphibians have been confused by the mild weather in Northern Virginia, thinking it’s spring. The first hard freeze this fall occurred overnight on Friday-Saturday, November 10-11, when the record-setting low temperature at Reagan National Airport (DCA) was 26°F. I hope this little one hunkered down like frogs are supposed to when it’s cold.

Related Resource: Spring Peepers, a blog post by Alonso Abugattas, Natural Resources Manager for Arlington County Parks, Virginia USA.

Copyright © 2017 Walter Sanford. All rights reserved.


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