Wednesday, September 16, 2020

Curve-lined Owlet: A most extraordinary caterpillar!

 

A typical Ohio woodland, especially in southern Ohio's Adams County, where I made this shot. The leaves in the foreground belong to Common Greenbrier, Smilax rotundifolia. Many hikers/woods-people know this plant because of its heavily thorned stems. Walking through a dense greenbrier patch is not fun.

But greenbriers - there are about a half-dozen Smilax species in Ohio - are ecologically important and play host to some very cool critters. One of them, the extremely bizarre Curve-lined Owlet Moth caterpillar, has been on my hit list for years. I have searched scads of greenbrier, which sometimes seems like the proverbial needle in a haystack quest, to no avail. Until September 8. The quest caterpillar is actually in the greenbrier in the above shot, but might be a bit tough to spot. You'll certainly see it well in the following images, though.

Chris Zacharias knew that I and a few others were hot on the trail of this owlet cat, and soon after he stumbled into one at the location above back on September 7 (his first, I believe) he sent John Howard and I messages with details. And so launched my first ever major caterpillar chase, as it was a two hour drive to reach the site. But the following day I headed out at dawn, and met John and Cheryl Carpenter at the site. Our hopes were high. If some annoying titmouse or other caterpillar-killing bag of feathers hadn't taken out the owlet, we were pretty confident about finding our Holy Grail.

The Curve-lined Owlet caterpillar in silhouette. Even from this, we get a sense of the strangeness of this tubular oddity.

Chris, detail-oriented as he is - not to mention sharp-eyed! - had sent explicit directions to the cat, which was feasting on a greenbrier plant about a half-mile down a woodland path. We headed that way, but were slowed by numerous greenbriers dotting the forest floor. Figuring that the moth that laid the golden egg that produced Zacharias's owlet caterpillar probably laid scores of other eggs in the area, we carefully inspected plants on the way.

The three of us were gathered around a small patch of greenbrier, when suddenly John uttered magic words: "Here's one!" And just like that, the spell was broken. Years of fruitless quests and thorny greenbrier searches fell by the wayside, and we drank in the charm of what may be our (in Ohio, at least) most bizarre caterpillar.

The Curve-lined Owlet caterpillar hangs from a stem of Common Greenbrier, Smilax rotundifolia. Greenbrier leaves are often dappled with brownish patches of necrotic tissue, and leaf margins often turn brown and crisp. Furthermore, plants are beset with filamentous tendrils. The caterpillar seems to mimic all these things, and they can be incredibly hard to spot in the thickets. I shudder to think how many I've been in close proximity to, but missed.

A dead greenbrier leaf snagged on a stem. You can see how well the caterpillar mimics the look of dead plant material.

PHOTO NOTE: To get the uniformly brown bokeh (background) in some of these photos, we just held a piece of cardboard a foot or so behind the subject. I always carry such things - including sheets of other colors - to help separate my subject from a cluttered background when needed. I believe the greenish background in the previous shot was achieved by having John get behind the caterpillar so we could use his shirt for the bokeh.

After a suitable admiration session of the first caterpillar, we worked on down the trail and located Chris Zachariah's animal. Not one, but two Curve-lined Owlet cats in short order! This owlet was on a different greenbrier species, Bristly Greenbrier, Smilax hispida.

Their appearance is truly remarkable - look at those pseudo-tendrils! - but equally astonishing is the caterpillar's behavior. If disturbed, or even jostled by a puff of wind, the caterpillar will begin to slowly twist and turn, just as a hanging dead leaf will. John has great video of this leaf-mimicking behavior. I think the larva is aided in its ability to slowly twist and pivot from a single point by the fact that it has only two sets of medial prolegs - most non-inchworm caterpillars have four middle sets of legs.

Photo by John Howard and used with permission

If all goes well for the strange caterpillar, this is what it will become. The Curve-lined Owlet moth is also a very interesting insect. The common name derives from that prominent whitish line across the wings. I have never seen the moth, and appreciate John allowing me the use of his image. I believe he has seen only one or two of the moths. I too hope to some day clap eyes on one.

The seeming scarcity of this species is a bit of a mystery. Its host plants are common, and often locally abundant. Obviously the caterpillars, in spite of being of a decently large size, are tough to spot. But I and others I know have spent many hours looking for them and you'd think if they were fairly common we'd occasionally encounter cats. It's not like we're brand new to the caterpillar-hunting rodeo. Also, the moths don't seem to turn up very often at moth sheets. Perhaps they just are not strongly attracted to light, though. Anyway, some mystery surrounds this extraordinary animal.

Major thanks to Chris Zacharias for tipping us to his discovery. The caterpillar was everything we hoped for and more. Besides and as always, this foray got us deep into some interesting habitat, and that night we hunted more caterpillars and set up moth lights. Scores of other interesting finds were made and in all it was a highly productive long day of exploration and photography.

Monday, September 14, 2020

Big backyard buck!

 

I glanced into the backyard "refuge" a few days ago only to see this stud. He was eating my beauty-berry plants. He may be the father of the two fawns that frequent my yard, and he may be looking to hook up with the doe again. Fine by me, as is his consumption of my backyard flora. He vaulted that fence as effortlessly as we'd step over a curb. I wrote about the fawns - at least one of them, a second appeared later - RIGHT HERE, and HERE.

Sunday, September 13, 2020

Concretions, galore


Hundreds of concretions litter the stream bed of Deer Creek in Pickaway County, Ohio. These concretions are composed of siderite, a type of iron carbonate, and many are massive. Over the eons, they have eroded from the much softer Devonian Shale. Shale cliffs line the western bank of the stream. The overall effect is quite dramatic and more than a touch surreal. It's like an army of rock blobs marching down the stream. I hope to get back here near the peak of fall color for more photography. Yesterday morning.

Thursday, September 10, 2020

Eastern Racer

An excellent find on last Tuesday's foray deep into Adams County (Ohio) was this fine Eastern Racer, Coluber constrictor. The animal was basking on sun-soaked leaf litter near the trail, and held tight hoping we'd pass without noticing. The last person in the party, John Howard, did, fortunately. These are exciting snakes. Racers exude a raw charisma, an incredible sense of awareness, and feral charm. They're tough, and other snakes - even venomous species - constitute part of their diet. The "racer" name is warranted. When this one had enough of our act, it shot away like a snapped bullwhip and was into a brush pile 20 feet away in seconds.

This trip was incredibly productive. We were after a true Holy Grail species, and found it. Along the way, many other interesting organisms such as this snake were found. I'll post about the prized find of our foray later. 

Monday, September 7, 2020

Nature: Despite "ick" factor, spiders play vital role as predator

A pirate spider lurks under a leaf/Jim McCormac

Nature: Despite "ick" factor, spiders play vital role as predator

September 6, 2020

NATURE
Jim McCormac

Like it or not, we’re entering prime spider season. And there’s a good chance YOU don’t like it. Arachnophobia is one of the most common fears. That’s a shame. Spiders are fascinating in behavior and appearance, and critical components of ecological webs.

There are approximately 650 spider species known from Ohio, and they come in many shapes and sizes. Many species overwinter in the egg stage, and the tiny spiderlings hatch in spring. By autumn, they have grown to an appreciable size and we notice many of the larger spiders.

Spiders represent an enormous group of apex predators, and are a vital part of maintaining ecological balance. As one of the most abundant group of hunters in most of our habitats, they collectively harvest an enormous volume of prey.

Silken webs of all sorts are the most conspicuous evidence of spiders plying their trade. Some webs are small and inconspicuous; others are large and showy. The raison d’ etre for these webs is universal: snare unsuspecting prey.

I was recently part of a group that converged at the ridgetop home of artist and author Julie Zickefoose in rural Washington County. Our party included Kelly Ball, Laura Hughes, Jessica Vaughan Melfi, Shila Wilson, and Julie and I.

A big part of the foray involved a nocturnal outing. We were mostly stalking moths and caterpillars, but found numerous interesting spiders. Like eight-legged vampires, many spiders emerge under the cloak of darkness.

As the night wore on, members of our party gradually slipped away, sanely returning to base camp and soft beds. Eventually it was just Laura and I and our flashlights exploring the inky woodlands. We finally ran out of steam at 3 am, but as is often the case, the post-midnight hours were productive.

At one point Laura summoned me to look at a spider lurking under a leaf. She had found a pirate spider, Mimetus puritanus!

There were good reasons to exalt over this find. One, pirate spiders don’t seem to be very common, or at least I have seldom seen them. Two, pirate spiders are arachnoid Rambos.

Almost all of our spider species are venomous, and other small animals mostly do well to avoid them. A pounce and a quick bite and they’re paralyzed toast. Even spiders must watch their steps when around other spider species.

The pirate spider isn’t intimidated by its venomous kin. Indeed, this small group – there are 8 species in Ohio and 156 species worldwide – specialize on hunting other spiders.

Unlike many other spiders, pirate spiders do not construct webs. Some species lie in wait, and when another spider happens by they pounce on it, kill it and eat it.

More interesting from a tactical perspective are the web-raiding pirate spiders. A hunting spider will sidle up to a web and gently twang a strand like a homicidal banjo player. This creates vibration throughout the web, and the rightful occupant will rush from its hiding spot and into the web to investigate.

The pirate spider then blitzkriegs the unsuspecting victim, and kills it.

Such dramas play out in abundance under cover of darkness. Horrifying as they may seem when gauged by human sensibilities, this is just the reality of Nature. And Nature is usually not very 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.

 

Friday, September 4, 2020

The Booby is dead, long live the Booby!

 

Photo by Jeff Harvey, posted with permission

We - the birders of Ohio - were rocked by some unfortunate news this morning. I received an email around 8:30 am from Bob Lane, along with some photos taken moments before by Jeff Harvey. Jeff had gone to see the Brown Booby once more - the subject of my prior post, RIGHT HERE - and soon found this wing floating under the booby's favorite perch tree.

Alas, there's no mistaking that wing. Some predator had taken out what had become perhaps the most famous vagrant bird in the Midwest.

Photo by Jeff Harvey, posted with permission

One of the juvenile Brown Booby's wings, dismembered. Who would have done this dastardly deed?

An obvious suspect, and some fingers have pointed in this direction, would be the juvenile Peregrine Falcon that I discussed in my previous post about this booby. However, I do not think the falcon is guilty. It is true that peregrines are primarily bird hunters. But they generally take much smaller prey than this booby, although the powerful falcons can kill ducks and smaller geese. But a Brown Booby weighs nearly a pound more than a peregrine, is nearly twice the length, and its wingspan is almost a foot and half longer. It'd be a tall order for a falcon to take out a booby and it probably wouldn't be worth the effort, especially in an area where more manageable prey abounds. Plus, I don't think a falcon would neatly sever the wings.

Also, the last report of the booby from yesterday came from around sunset or even a bit after, and the booby was settled into its favorite perch tree. While Peregrine Falcons are known to occasionally hunt at night, such behavior is not typical and the species is normally a diurnal hunter. While the booby kill could have been made around dawn this morning, before Jeff or other birders arrived, it seems likely that something got it last night.

I would guess Great Horned Owl. These powerful owls are at the top of the avian food chain in these parts, and are known for dismembering body parts of larger victims. Especially the head. I don't know if anyone has found or will find the rest of the booby carcass, but if it turns up it'll be interesting to see if it's headless or at least partly so. Great Horned Owls are known to take birds up to the size of mergansers, Short-eared Owl, and even - at least once - an Osprey. A booby roosting more or less in the open in a dead tree would seem to be a sitting duck for a hungry owl.

Scores of people came to see the celebrity booby during its ten days at Nimisila Reservoir. There's no telling if the wayward youngster would have made its way back to southern oceans, eventually. But that's a moot point now. Fortunately, in the bigger picture, Brown Booby is probably the most numerous of the world's half-dozen booby species, with a population likely numbering several hundred thousand. So, while many of us will lament the loss of the Ohio bird, the species will carry on. 

Monday, August 31, 2020

Brown Booby makes first Ohio appearance!

Birding by boat. A small flotilla of birders/photographers (the two groups are largely inseparable these days) watches what is easily the rarest bird in Ohio right now. On August 25, Henry Trimpe discovered a juvenile Brown Booby, Sula leucogaster, on Nimisila Reservoir in Summit County.

I finally made the journey up to see the bird yesterday. By then, the initial madness had worn off, and while dozens of people visited during my time, it wasn't the heavier crowds of days prior. The young booby seems quite at home here, and I figured it would linger. It's still present today.


Nimisila Reservoir and vicinity is a beautiful, watery region, and very much to the liking of "fish hawks", or Ospreys. I arrived at 7 am, and the first bird that I heard upon stepping from the vehicle was an Osprey. Their high-pitched piping whistles were a constant part of the soundscape, and perhaps six of the fish-eating raptors were present.

I saw lots of interesting birds during my five hours at Nimisila, but this beauty was what we had all come for: the young Brown Booby. The name, of course, provides constant fodder for witty repartee and interesting reactions from non-birders.

Non-birder: "So, what are you all looking at?"

Birder: "A Brown Booby"

Hilarity ensues.

The funny name arises from the Spanish bobo, which means "dunce". Sailors became very familiar with these birds early on, and thought them stupid due to their extraordinary tameness. Seabirds that nest on isolated islands and have little to no human contact often show little fear of people. But the misinterpretation of their intellect did give us the comical name. For more interesting information about boobies, and the sources and meanings of North American bird names, get a copy of Gary Meiter's book Bird is the Word. Go HERE to read more about this book, and HERE to get a copy.

Brown Boobies are an oceanic species, very rarely venturing inland and onto fresh water, especially this far north. That said, there is an Indiana record and several records from the eastern end of Lake Erie, so it's not altogether unexpected for this species to appear in Ohio.

While the numerous Osprey did not bother the booby in the slightest, this young Peregrine Falcon certainly did. Early in my visit, the falcon rocketed in and chased the booby off its favorite perch in a dead tree along the shoreline. It then proceeded to chase our rare visitor around the lake, forcing it onto the water and making several dives at it. I don't really think the falcon was attempting to kill the booby; it was probably just out for some fun. After thoroughly exerting its dominance, the Peregrine flew back to the booby's exact perch and sat for a while - that's where the above image was made.


While boobies may look somewhat clumsy and comical when grounded, they transform once airborne. Fast and powerful in flight, the Brown Booby specializes in catching flying fish when in its normal marine haunts. That takes extreme aerial prowess. The Nimisila vagrant seemed to be doing fine in capturing the lake's freshwater fish, and treated viewers to regular flights. Notice the heavy molt going on with this bird.


It's hard to say what the fate of this young booby will be. It likely was forced off the Gulf of Mexico and way to the north by Hurricane Laura, which formed and rapidly grew in intensity a few days prior to the bird's appearance here. Saltwater birds often don't fare well in the long term in freshwater habitats. With luck, the Brown Booby will make its way back south and onto the ocean. But whether it has any innate instinct as to where it should be remains unknown.

One thing is for certain. Many people will be keeping an eye on the bird, and it will be interesting to see how this booby situation plays out.
 

Curve-lined Owlet: A most extraordinary caterpillar!

  A typical Ohio woodland, especially in southern Ohio's Adams County, where I made this shot. The leaves in the foreground belong to Co...