Wednesday, December 28, 2022

At the Cave #2

This could, and perhaps should, have been titled A Year at the Cave or Cats at the Cave since bobcats are the stars of the videos from the first eleven months of 2022. Videos from the cave have appeared before, most recently a bit over a year ago

It appears that, along with a porcupine, an opossum and possibly a raccoon, a female bobcat may have taken up residence in the cave on at least a part-time basis. Not only did a bobcat repeatedly use the cave during the winter but, as you will see, it scent marked the camera including the lens. Later in the year two bobcat kittens appeared and spent time in front of the camera.

The bobcat kittens honed their hunting skills by playing with a dead white-footed mouse. There’s no way of telling whether a kitten caught and killed the mouse or if the adult had provided the mouse. Hopefully the kittens have become adept enough at catching their own food to live long lives here on the edge of the Allegheny Plateau.

Wednesday, December 21, 2022

Feathers and Wedges

We all know what feathers are – they cover the skin of birds; as for wedges, those are used to split firewood. OK, but what on earth do they have to do with each other – if anything?

We’re not going to talk about birds’ feathers or splitting a winter fuel supply. Here we’re going to talk about the things also known as plugs and wedges, wedges and shims and pins and feathers. Confused now?

Feathers and wedges are ancient tools (still available from a number of dealers) used to split stone.

Ancient they may be, but they’re still one of the easiest and simplest way to shape stone. They were used to shape the stone used in Europe’s cathedrals, to cut the flagstone for American city sidewalks and in the production of millions of gravestones in cemeteries.

To cut stone using feathers and wedges the first step is to drill a series of holes about six inches apart in a straight line. In olden times a star drill and hammer were used to drill the holes, now a powered drill is used. Following that, two feathers and a wedge are inserted in each hole.

Once all the feathers and wedges are in place they are gently struck with a hammer, one after another and the process repeated until the stone splits (the beginning of the split can be seen in the photo above).

Stones cut by feathers and wedges often show the telltale holes drilled in the process as seen in some of the stones in this bridge abutment –

In the Big Woods there’s a large boulder which someone tried to split with feathers and wedges, someone who apparently had heard about the technique but didn’t know enough. The drilled holes were too far apart to produce a straight cut.

And, because the holes are too far apart to effectively split the stone or even split it at all, several sets of feathers and wedges are stuck in the holes and have been there for many decades.

These tools and their use have been handed down through the ages and are still very effective – when they’re used correctly.

Wednesday, December 14, 2022

Felsenmeer - a "sea of rock"

Felsenmeer is a German term meaning “sea of rock” and is used to describe blockfields that formed during glacial epochs when temperatures just south of the glaciers fluctuated frequently. Repeated freezing and thawing of water trapped in small cracks in the bedrock broke the rock into angular boulder-sized rocks. 

At that time there was little vegetation on the ground and what there was resembled the vegetation now growing in the high arctic.

Two of Pennsylvania's best known felsenmeers are the Hickory Run Boulder Field in Hickory Run State Park and the River of Rocks in Hawk Mountain Sanctuary. Felsenmeers occur throughout much of Pennsylvania’s Ridge and Valley Region, some fairly small and some quite large. Little of the Ridge and Valley Region in central Pennsylvania was glaciated in either the most recent glacial era or the preceding one. But most or all of the region had the tundra-like conditions in which these block fields were created.

Now, thousands of years later, these areas of broken rock remain, some on steep hillsides and some on fairly flat areas.

The blockfields, as barren as they appear, do provide habitat for a few species of wildlife. Turkey vultures raise their young in voids between the rocks and Allegheny wood rats build their bulky nests in narrow spaces between the boulders. Unfortunately, Allegheny wood rats are considered threatened in Pennsylvania as their populations have fallen drastically due to the raccoon roundworm, an internal parasite. Here's a photo of the only one I’ve ever seen – in a felsenmeer. 

A number of years ago members of our hiking group explored a rather large felsenmeer on a steep hillside –

Over time vegetation is gradually creeping into the felsenmeers as the spaces between the boulders accumulate decayed vegetation –

But the felsenmeers will still be gracing the Ridge and Valley Region for thousands of years. 

Wednesday, December 7, 2022

Summer and Fall on the Log Bridge

For those of us who operate camera traps fallen logs are the gift that keeps on giving. The best logs are those that span an obstacle: a rock ledge, steep bank or stream. In this post we see videos of the critters that used a log bridge across a small stream during the summer and fall.

This log bridge was once a fairly large eastern hemlock that, when it fell, created a route for mammals to cross the stream without getting wet feet; birds also use the log bridge as a perch with clear flight lines in an area of dense shrubs. Earlier videos from the log bridge were posted here 

Several species new to videos from this spot appeared, the most impressive being a juvenile great horned owl –

Here they are, the best videos from the summer and fall at the log bridge –

Unfortunately, the videos from November consisted of over 500 clips, taken in less than 48 hours, of three blades of grass blowing in the breeze and nothing else; the grass can be seen in the last few clips in the video. Those 500 clips filled the camera’s memory card and the camera was then removed in anticipation of hunting seasons.

Try, try again in late winter.