Posts Tagged ‘Occoquan Bay National Wildlife Refuge’

Predator and prey

February 8, 2018

A Black and Yellow Argiope (Argiope aurantia) was spotted during a photowalk along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. A female Common Whitetail dragonfly (Plathemis lydia) is trapped in the spider web.

“Eat or be eaten” is perhaps the most fundamental law of nature. Predator-prey relationships can change suddenly: one minute a predator, such as a dragonfly, is hunting for its next meal; next minute the dragonfly becomes the prey and is a meal for another predator, such as a spider, elsewhere in the food web.

Copyright © 2018 Walter Sanford. All rights reserved.

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Legend of the Woolly Bear caterpillar

January 29, 2018

A “Woolly Bear caterpillar” was spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Wooly Bear caterpillar is the larval form of the Isabella Tiger Moth (Pyrrharctia isabella).

According to legend, …

The Woolly Bear caterpillar has 13 distinct segments of either rusty brown or black. The wider the rusty brown sections (or the more brown segments there are), the milder the coming winter will be. The more black there is, the more severe the winter. Source Credit: WOOLLY BEAR CATERPILLARS AND WEATHER PREDICTION – USING WOOLLY WORMS FOR A WINTER FORECAST, The Old Farmer’s Almanac.

Is the legend scientifically valid?

…this myth has been around since, you know, the colonial times. But in 1948, this curator of entomology from the American Museum of Natural History, Dr. Howard Curran, he did a little study. He went out to Bear Mountain, New York, and he counted the woolly bears, the bands – the brown bands of the woolly bear there. And he counted about 15 different specimens, and he made a prediction. Source Credit: The Myth of the Woolly Bear, National Public Radio.

Problem is, a sample size of 15 is insufficient for making meaningful conclusions. So looking at one caterpillar, as I did, is completely meaningless. Nonetheless, I always think of the legend whenever I see a Woolly Bear and wonder what it tells me about the upcoming winter.

Related Rescources

Copyright © 2018 Walter Sanford. All rights reserved.

Slaty lady

January 27, 2018

Mike Powell and I were searching for Fine-lined Emerald dragonflies at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. As we were walking along one of many gravel trails at the park, I spotted a dragonfly perching atop an unusually tall grass stem.

16 SEP 2017 | Occoquan Bay NWR | Slaty Skimmer (mature female)

This individual is a mature female Slaty Skimmer dragonfly (Libellula incesta). Although Mike and I were disappointed we hadn’t found a Fine-lined Emerald, I was happy to shoot a photograph worthy of my Odonart Portfolio.

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Red-spotted Purple butterflies

January 25, 2018

A Red-spotted Purple butterfly (Limenitis arthemis astyanax) was spotted during a photowalk along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

About a week later, another Red-spotted Purple was spotted during a walk around Mulligan Pond at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA.

The appearance of Red-spotted Purple seems to be somewhat variable.

Copyright © 2018 Walter Sanford. All rights reserved.

Question Mark

January 23, 2018

A Question Mark butterfly (Polygonia interrogationis) was spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Two field marks can be used to identify this butterfly. First, notice the row of four dark spots on the dorsal side of its forewings (highlighted in an animated GIF by Deb Platt).

Second, notice the silver-white question mark shape on the ventral side of its hind wings (highlighted in an animated GIF by Deb Platt).

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Different point of view

January 15, 2018

The first photo shows “The Osprey’s at Belmont Bay,” as seen from the opposite side of Belmont Bay. “The Osprey’s” community shares a common boundary with Occoquan Bay National Wildlife Refuge, located to the left of this photo.

11 JAN 2018 | Prince William County, VA | The Osprey’s at Belmont Bay

The next photo shows the near shoreline of Belmont Bay. The bay is almost completely covered by ice after two weeks of below-freezing temperatures.

11 JAN 2018 | Fairfax County, VA | Belmont Bay

Notice the duck blind located in the water.

11 JAN 2018 | Fairfax County, VA | Belmont Bay

The following photo shows a dock and boat ramp located at the mouth of a small stream that is a tributary of Belmont Bay.

11 JAN 2018 | Fairfax County, VA | dock and boat ramp

The next photo is located upstream from the dock and boat ramp.

11 JAN 2018 | Fairfax County, VA | small tributary of Belmont Bay

The last photo shows a location far upstream from Belmont Bay. The stream is located at the bottom of a steep-sided valley.

11 JAN 2018 | Fairfax County, VA | small tributary of Belmont Bay

Tech Tip: I used my Panasonic Lumix DMC-FZ150 superzoom camera to shoot the landscape photos 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 © 2018 Walter Sanford. All rights reserved.

Top 10 Photos of 2017

January 1, 2018

The following gallery shows 32 finalists for my “Top 10 Photos of 2017.” The photos are presented in reverse-chronological order beginning in November 2017 and ending in April 2017.

The Top 10 photos will be selected using reader feedback. Please enter a comment at the end of this post listing the number for each of your 10 favorite photos. If listing 10 photos is asking too much, then please list at least five photos, e.g., No. 5, 8, 14, 17, 21, etc. Thanks for sharing your selections, and thanks for following my photoblog!

No. 1

No. 2

No. 3

27 OCT 2017 | MRA | Autumn Meadowhawk (mating pair, “in tandem“)

No. 4

No. 5

No. 6

No. 7

No. 8

No. 9

No. 10

No. 11

No. 12

No. 13

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No. 21

20 JUN 2017 | OBNWR | Calico Pennant (immature male)

No. 22

No. 23

10 MAY 2017 | HORP | crayfish (underwater)

No. 24

No. 25

No. 26

No. 27

No. 28

No. 29

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No. 31

No. 32

Editor’s Note: The following location codes are used in some photo captions, shown above.

Copyright © 2018 Walter Sanford. All rights reserved.

New discoveries in 2017 (non-odonates)

December 30, 2017

I’m an equal opportunity photographer. Although I tend to focus on photographing odonates (dragonflies and damselflies) I will photograph anything interesting that catches my eye. This retrospective features non-odonate new finds for 2017.

House Finch (Haemorhous mexicanus)

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

A House Finch (Haemorhous mexicanus) was spotted in the parking garage at the Beacon of Groveton, Fairfax County, Virginia USA. This individual is a male.

Eastern Hog-nosed Snake (Heterodon platirhinos)

An Eastern Hog-nosed Snake (Heterodon platirhinos) was spotted at Hemlock Overlook Regional Park (HORP), Fairfax County, Virginia USA.

Mayfly (Hexagenia sp.)

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

Northern Red-bellied Cooter (Pseudemys rubriventris)

A male Eastern Amberwing dragonfly (Perithemis tenera) was spotted perching on the nose of a Northern Red-bellied Cooter (Pseudemys rubriventris), at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA.

Blister beetle (Meloe sp.)

A blister beetle (Meloe sp.) was spotted at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Wild Turkey feathers (Meleagris gallopavo)

A tail feather from a Wild Turkey (Meleagris gallopavo) was photographed in situ along Easy Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Copyright © 2017 Walter Sanford. All rights reserved.

New discoveries in 2017 (odonates)

December 28, 2017

There’s always more to discover/learn! My odonate-related new discoveries in 2017 are presented in reverse-chronological order.

Fine-lined Emerald dragonfly

A Fine-lined Emerald dragonfly (Somatochlora filosa) was spotted at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is one of several males spotted during a period of a week-or-so in mid-September 2017.

Immature male Calico Pennant

20 JUN 2017 | OBNWR | Calico Pennant (immature male)

A Calico Pennant dragonfly (Celithemis elisa) was spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is an immature male. Notice its coloration is similar to female Calico Pennants.

Allegheny River Cruiser dragonfly

An Allegheny River Cruiser (Macromia alleghaniensis) was netted by Mike Blust at Hardware River Wildlife Management Area, Fluvanna County, Virginia USA. This individual is a male.

Harpoon Clubtail dragonfly

09 JUN 2017 | Highland County, VA | Harpoon Clubtail (male)

A Harpoon Clubtail dragonfly (Phanogomphus descriptus) was spotted at “Straight Fork,” Highland County, Virginia USA. This individual is a male. Sincere thanks to fellow Virginians Karen Kearney and Mike Boatwright for guiding me to this unique high-elevation habitat.

It’s worth noting that I saw two more new species during the same trip: Riffle Snaketail (Ophiogomphus carolus); and Dot-tailed Whiteface (Leucorrhinia intacta).

Those who know me well are familiar with one of many “Walterisms”: “I haven’t ‘seen’ something until I have photographed it.” My rationale is two-fold: 1) A photograph verifies a sighting. 2) The detail visible in a good photograph exceeds the acuity of the human eye. Suffice it to say I saw two other species but haven’t seen them. Makes sense to me!

Swift River Cruiser dragonfly

A Swift River Cruiser dragonfly (Macromia illinoiensis) was spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is an emergent/teneral female.

Spine-crowned Clubtail dragonfly

A Spine-crowned Clubtail dragonfly (Hylogomphus abbreviatus) spotted along Bull Run at Hemlock Overlook Regional Park, Fairfax County, Virginia USA. This individual is a male. A female was spotted on the same day at a nearby location.

Epitheca cynosura exuvia

A Common Baskettail dragonfly (Epitheca cynosura) exuvia was collected at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Epitheca princeps exuvia

05 MAR 2017 | Prince Baskettail (Epitheca princeps) | exuvia (face-head)

A Prince Baskettail dragonfly (Epitheca princeps) exuvia was collected from an unknown location. This specimen was on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

Copyright © 2017 Walter Sanford. All rights reserved.

Milkweed seed pod

December 12, 2017

A solitary milkweed seed pod was spotted during a photowalk along Easy Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. According to Drew Chaney, a.k.a., “plantmandrew,” it is either swamp milkweed or butterfly weed, more likely the latter.

Since it was a windy day, I used a shutter speed of 1/1000s in order stop the motion of the silky seeds blowing in the wind. I also used an external flash unit and -2 ev exposure compensation for the first photo.

16 NOV 2017 | Occoquan Bay NWR | milkweed seed pod

I used the same shutter speed for the last photo, but turned off the flash and reset exposure compensation for 0 ev.

16 NOV 2017 | Occoquan Bay NWR | milkweed seed pod

Although I like both photos, this may be one of those rare times when I prefer the no-flash image. Which one do you prefer?

Copyright © 2017 Walter Sanford. All rights reserved.


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