Saturday, October 21, 2017

The Milky Way

As always, click on the photo to enlarge. If you're bored, try to count all of the stars.

The cloudy band of stars known as the Milky Way cuts diagonally across this exposure. I made the image a week ago in a remote southern Ohio forest, where light pollution is minimal. In much of the state, light pollution from towns and cities is now too intense to see many celestial objects. At this locale, on this night, the stars were visible to a degree I've seldom seen in Ohio, at least in a long time. As Carl Sagan would have said, there were "billions and billions" of stars. He wouldn't have been exaggerating. The Milky Way - our solar system - is thought to contain as many as 400 billion stars.

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Tuesday, October 17, 2017

A cooperative Eastern Screech-Owl (with comments on low-light photography)

f/4, 1/100th, ISO 400, + 1/3rd exposure compensation

An Eastern Screech-Owl peers from its roosting hole - a cavity in a gnarled box-elder. I made this image and those that follow yesterday at a local park. James Muller, a sharp birder and regular at this place, was making the rounds the other day when he heard agitated chickadees and other songbirds mobbing something. Astutely, he sought out the source of their angst and found the owl.

Screech-owls tend towards the tame, but this one takes the cake. It could care less about people watching and photographing from the trail, which is only about 25 feet or so away. As we represent neither food nor foe, the owl would rarely even cast a glance our way. Fortunately, the owl has been spending a fair bit of time sitting at the cavity entrance during the day, allowing its admirers to fawn over it.

I saw an opportunity to make some images of one of my favorite species, and headed over as soon as time permitted. Making nice clean images of the owl was not totally straightforward though, due to very dim (shaded) light conditions. There are some ways to combat low light, and I'll share them at the end of the post. Make note of the camera settings under each photo. All of them were made with the Canon 5D IV mounted on a Gitzo tripod, with the Canon 500mm f/4II lens, and all but the first image with the Canon 1.4x teleconverter (making for a 700mm lens).

f/9, 1/40th, ISO 500, -1/3rd exposure compensation

One of the rare times the owl deigned to look into the camera, showing us its slightly cross-eyed look.

f/9, 1/6th (yes - one-sixth of a second!), ISO 200, +1 stop exposure compensation

The little owl dozes, apparently enjoying the warmth of a sunny day and the few rays that penetrate his wooded locale. His mini-siestas seldom lasted long, as marauding Carolina Chickadees or vultures passing over would often grab the owl's attention.

f/9, 1/6th, ISO 500, +1 stop exposure compensation

Chickadee alert! The owl snaps his attention towards the annoying chickadees that routinely stopped by to loudly scold him. They would often approach within a few feet, and when the owl was down in his hole, would alight on the edge of the cavity and shout chickadee expletives into his lair. While small rodents such as mice often form a staple of a screech-owl's diet, they will certainly bag small songbirds if chance permits, hence the chickadees' dislike of the predator.

This is the camera rig set up on the owl's cavity, which is circled in red. The path made a nice operating surface that was far enough away to avoid any bother to the owl. As previously noted, the major problem was poor light. One way around that would be to use flash, but I won't do that with an owl and I don't think anyone should. The bright pulses of light would almost certainly annoy the owl, and likely send it back in the hole, or possibly even flush it. Even if not, photographers sending Better Beamer-boosted flash onto the bird would most certainly annoy other people who are admiring the bird, and thus create unnecessary conflict.

So, what to do? In such situations, ISO drives much of my decisions regarding camera settings. Although cameras are getting increasingly better at processing higher ISO settings, lower ones are always better. The higher the ISO, the grainier (noisier) the image becomes. The lower the ISO, the cleaner and more noise-free the image. Thus, the lower the ISO, the better the image. ISO is the digital equivalent of film speed from the olden days. Back then you would use 100 film speed for bright conditions, which would yield the cleanest images. 400 or 800 and up speed film for darker conditions, but with the trade-off being grainier images.

With my first image - which was one of the first that I made of the owl - I had the 500mm lens wide open at f/4, at which it harvests the most light. This allowed a fairly fast shutter speed of 1/100, with the ISO only reaching 400. The 5D IV handles higher ISO's pretty well, but I really dislike shooting at anything over ISO 800, and do my best to go lower than that. My issue here was that I really wanted to shut the aperture down to provide better depth of field as well as some increased sharpness, but that reduces the light that enters the camera even further. Also, after the first round of images, I decided I wanted to put on the 1.4x teleconverter to increase the focal length of the lens to 700mm. By doing that, the aperture goes to a minimum of f/5.6.

Fortunately, owls may as well be feathered rocks when they're roosting. They do move, but more often they just sit stock still, so shutter speed becomes less of an issue. So, with the camera rig firmly mounted on the tripod, I had a stable working platform. I then used "live view" which displays the scene on the screen on the back of the camera. In this mode, the internal mirror is locked up, which prevents even the faint shudder caused by the mirror's movement when the shutter is tripped. To further reduce any possibility of camera movement, I had a remote shutter release plugged into the camera. You can see that hanging off the tripod in the photo above. With this setup, the camera remains absolutely motionless when I trigger it, allowing me to use insanely slow shutter speeds caused by a small aperture of f/9 and very low ISO settings. As long as the owl did not move during the exposure, the slow shutter speed doesn't matter, and I get far cleaner images than if I shot at fast shutter speeds that would have required ISO settings that probably would have had to range to 3200 or even well above.

f/9, 1/6th, ISO 1000, +1 exposure compensation

As the day's end approached and light worsened, my ISO had to increase to maintain the same settings. This is one of the last photos that I made, near twilight. The ISO hit 1000, and that's about as high as I want to go with that if at all possible. The image, even with this tight crop, still looks pretty clean and sharp (and I greatly compress the images posted on this blog). And that's at one-sixth of a second!

While the techniques described here are well known to landscape photographers, they can be applied to birds and other animals, as long as they remain motionless long enough for the exposure to be made.


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Thursday, October 12, 2017

A visit to a fen

Ohio Goldenrod, Solidago ohioensis, brightens a largely senescent prairie fen on an early October day. The goldenrod is well named. It was discovered and described to science from a prairie near Dayton in the 1830's.

The photo above is perfectly level, I can assure you. Pressurized artesian ground water provides hydrology for this place, and the main meadow is somewhat dome-shaped, thus the sloping meadow.

PHOTO TIP: Many cameras have a built-in level, and this tool is useful in framing landscape compositions shot from a tripod. That's how I know the above image is level. I use mine all the time. With Canon cameras, just tap your "info" button until the level appears on the camera's back screen (usually two taps). A horizontal line will appear across the screen. When it's red, the image is not level. Just adjust the camera until the line turns green, and you're level.

A photographer friend and I visited this fen in northern Ross County, Ohio, last Sunday. On this day, rain strongly threatened, and cut the trip short. It's a bit of a bushwhack to get back in there, and I didn't want to get caught in a deluge with my equipment. Nevertheless, there was still time for an hour or two of fen exploration, and even on this late date, there was much to see.

The main quarry was botanical in nature; the gorgeous (Small) Fringed Gentian, Gentianopsis virgata. I add the "small" parenthetically as there is another species, G. crinita, which is very similar and apparently is "greater" in some way.

This fen, although only encompassing an acre or two of open meadow, is loaded with gentians. Hundreds of plants to be sure. The thing about fringed gentians is that the flowers are photosensitive, so if you visit them on a heavily overcast day as we did, the flowers will not be fully expanded. When they are, the petals expand and splay their tattered, fringed lobes outward. A quite stunning effect, but even when the flowers remain tightly enrolled on a cloudy day, they still look good. See above.

PHOTO TIP II: Flowers can be tough to photograph well, for a number of reasons. A common difficulty is that they're often amongst lots of botanical clutter - grasses, sedges, other plants. That's certainly the case with these gentians. I carry about a dozen pieces of thick card stock (about 8.5 x 11) in my backpack, and each is a different color. By holding one behind my subject, I can dramatically alter the background (bokeh) and temporarily hide the clutter from view. In this case, a slightly off-white color created, to me, a very pleasing backdrop, giving the image the look of a watercolor painting.

Perhaps best of all was this beautiful little Eastern Gartersnake, encountered while basking in the boughs of a spicebush. It was a bit cool, and the snake was not particularly active. Its slothfulness allowed me to sidle in front of it, then drop to the ground to get on its level. The animal met my gaze head on, occasionally flicking its tongue. I was using gentle fill flash from a Canon Speedlite, and the angle I was at did not illuminate the snake's left side. But I rather like the effect. F/16 provided enough depth of field to show the snake's sinuous body extending back into the shrub. After a handful of shots by its admirers, the serpent darted away.

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Tuesday, October 10, 2017

White-haired Goldenrod, Solidago albopilosa, a major rarity back from the brink

A large sandstone overhand forms an impressive cliff deep in the Red River Gorge of Kentucky, part of the Daniel Boone National Forest. This is a beautiful area, full of stunning scenery and interesting flora and fauna.

I made my first foray here in the early 1990's. It was a one-day whirlwind trip to study one of the rarest goldenrods known, the White-haired Goldenrod, Solidago albopilosa. At that time, the plant had just been listed as Federally Threatened - among the rarest of the rare. Thus, some research money was available to study this poorly known plant, and I was along with a researcher who was contracted to do work with the goldenrod. That day sped by, and I had long wanted to return and spend more time in the gorge.

Fast forward to fall 2013 and a return trip. This expedition was a bit late for seeing the goldenrod at peak bloom, and the mission targets were different, mostly nocturnal creatures. We scored big on all fronts, and it made me want to return again. After all, the Red River Gorge is only about four hours from my home in Columbus, and that's next to nothing.

So, finally, I got a chance to return in the first weekend of September 2017 and resolved to revisit and photograph the White-haired Goldenrod. The timing was pretty good and the plants were starting to bloom well. As an expected plus, there was a virtual goldmine of other flora and fauna to see, as well as scores of beautiful landscapes. I still haven't finished curating all of those photos.

This image was made after progressing further along the same cliff line shown above. The recess cavern gets bigger, and the flora gets more interesting. This spot turned out to be a fantastic site for a thriving White-haired Goldenrod population. A number of other noteworthy plants grow here, perhaps of greatest interest to a botanist, the Appalachian Filmy Fern, Trichomanes boschianum.

All of the grayish-green ground cover in the bottom right hand corner of the image is the primary target, though. A vigorous stand of the goldenrod bearded nearly the length of the bottom of the cliff. It's finicky stuff, generally only growing in soft decomposed sandstone in near perennial deep shade at the bases of sandstone cliffs. These sorts of habitats are very prone to disturbance from people, many of whom cannot resist scrambling through every nook and cranny of such places. Fortunately, a large chunk of the goldenrod population at this site - and many similar ones - was fenced off to prohibit trespass, along with stern warnings to keep out.

A closer view of a stand of White-haired Goldenrod. It's a very delicate plant, as are many plants who grow in the near-constant gloom of rock edifices such as this. As noted above, probably the biggest threat to rockhouse plants is people. Once the mobs are allowed unfettered access to a such sites, plants such as the goldenrod are quickly trampled out of existence. Ohioans need only look to the popular rockhouses of the Hocking Hills for evidence of this.

A closer view of a flowering stem. The golden flowers are axillary, and the coarsely serrate leaves are fat and egg-shaped. Both stem and leaves are densely beset with long soft white hairs, which give the plant both its common name, and scientific specific epithet albopilosa (albo (white) pilosa (soft hairs).

This distinctive plant, surprisingly, went undiscovered until 1940, and was not formally described until 1942. It was the venerable Ohio botanist Emma Lucy Braun who first brought the plant to light - one of a number of plants species that she discovered and described to science.

Nearly all of the White-haired Goldenrod populations are in the Red River Gorge, in only three adjoining counties. At the time of its listing as Federally Threatened in 1988, less than 40 small sites were known. The Red River Gorge is a Mecca for people and a favorite locale for rock climbers, and human traffic was taking a serious toll on delicate cliff habitats. Kudos to the Forest Service for going to great lengths to protect many of the goldenrod populations by fencing out people, redirecting trails, and utilizing other measures. Largely because of their conservation efforts, and partners like the Kentucky Nature Preserves Commission, the rare plant has flourished and now there about 120 populations.

White-haired Goldenrod was removed from Federal listing in 2016 - a good example of the Endangered Species Act serving its function very well. As long as current protection efforts remain in place, the goldenrod should continue to flourish.

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Tuesday, October 3, 2017

Nature: Wasp turns caterpillars into zombified protectors

A Glyptapanteles wasp cocoon guarded by a parasitized saddled prominent caterpillar

October 1, 2017

NATURE
Jim McCormac

George Romero, who died in July, made some of the greatest horror flicks ever. He is especially known for his films about zombie apocalypses, such as “Night of the Living Dead.”

I don’t know if Romero knew anything about the subject of this column, but I’m sure he would have been intrigued.

During a nocturnal field trip in southern Ohio’s Scioto County in August, my group noticed an odd thing. Plastered to a tree branch was a strange, fluffy cocoonlike object. Perched atop was a saddled prominent caterpillar, a type of moth larva.

Upon closer inspection, I realized what we were seeing: a zombie caterpillar, rewired and forced to act as guardian of its killers.

If you were a being that reincarnates, choosing a caterpillar for your rebirth would be a bad idea. You could take myriad forms, as there are more than 2,000 species of moths and a bit more than 100 species of butterflies in Ohio, all of which are caterpillars for part of their life cycle. But the problem is they have a mortality rate near 99 percent.

These tubular bags of goo are preyed on by all manner of beasts. Songbirds snap them up, mice relish them, and scores of predatory insects feast on them.

To survive this predatory gauntlet, many moths and butterflies practice carpet-bombing reproduction. A female might lay hundreds or thousands of eggs to ensure that a few of the offspring survive to the adult reproductive stage. The rest will fuel the food chain.

Perhaps no caterpillar predator is stranger or more horrifying than the tiny wasps in the genus Glyptapanteles. These wasps are parasitoids, and it’s worth noting their difference from parasites.

Lice, ticks and chiggers are all parasites. They’re annoying and might even carry diseases, but they do not, typically, directly kill their hosts. Not so the parasitoid. The ultimate fate for their hosts is usually death, and sometimes in grislier ways than those concocted by Romero’s fertile imagination.

A female Glyptapanteles wasp seeks out appropriate caterpillar hosts, and when she finds one, the attack commences. She alights on the victim and uses a needlelike ovipositor at the end of her abdomen to inject several dozen eggs.

The eggs quickly hatch, and the wasp grubs feast on the caterpillar’s nonvital tissues and fluids. Eventually, the mature larvae exit en masse by boring holes through the caterpillar’s skin. The shed skins of the grubs’ final molt apparently plug their exit holes.

Upon emergence, the grubs begin spinning silken cocoons under the caterpillar, which, incredibly, begins helping them by enshrouding all of the wasp larvae in a thick, protective bag of its own silk.

Once all of the wasp grubs are safely ensconced in the silken shelter, the caterpillar stands guard atop the structure, thrashing its body at any potential predator that dares to encroach. The mechanisms that trigger the “zombification” of the caterpillar are imperfectly known, but it’s probably due to some chemical brew injected by the wasp.

By the time the grubs transform and emerge as wasps, the caterpillar will be dead or nearly so, having given its life to help ensure the survival of its nemesis.

In spite of all the apparent protections, some predators slip through and attack the grubs. Note the tiny wasp in the photo. It might be a “hyperparasitoid,” a predator of the predator. The wasp appears to be injecting eggs into the grubs within the cocoon.

Nature is seldom Disneyesque.

Naturalist Jim McCormac writes a column for The Dispatch on the first, third and fifth Sundays of the month. He also writes about nature at www.jimmccormac.blogspot.com.

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