Carnegie Museum of Natural History

One of the Four Carnegie Museums of Pittsburgh

Powdermill

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Annoying, amazing, silk

By John Wenzel

spider spinning silk
Photo credit: Andrea Kautz

The woods are full of spiders in late summer, as any hiker knows. Spider silk strands and webs are annoying, and one of the main offenders in our area is Micrathena gracilis, a small spider that likes to build webs across open spaces a couple of yards wide, like footpaths. These diligent weavers have striking spiky abdomens, and other species in the genus are quite spectacular for looking like thorns.

Spiders make several kinds of silk that are used for different purposes. The sticky silk of the spiral capture web is different from the frame lines that support the web and connect it to the vegetation nearby. Frame lines have greater tensile strength than steel.

One of the largest web spinners, the golden orb weaver (Nephila), makes frame lines commonly more than 15 feet long to support a web that can be more than three feet wide. These spiders are abundant in Florida and warm forests world-wide. Their silk is a lustrous gold color naturally.

silk lamba
Photo credit: Simon Peers and Nicholas Godley

Recently, Simon Peers and Nicholas Godley led a team in Madagascar that worked for years to harvest silk from more than a million of these spiders to make stunning gold cloth, both in their traditional native style (a lamba) and also a European-style cape. These have been displayed in the Victoria and Albert Museum in London, the American Museum of Natural History in New York, and currently at the Royal Ontario Museum in Toronto.

spider silk cape
Photo credit: Simon Peers and Nicholas Godley

More on this unusual project and how they created these museum pieces from golden spider silk is available at godleypeers.com.

John Wenzel is the Director at Powdermill Nature Reserve, Carnegie Museum of Natural History’s environmental research center. He has published research on the evolution of web building behavior. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Black Bears at Powdermill

By Andrea Kautz

Recently, the PA Game Commission brought a black bear to Powdermill to release in the nearby state forest. It was a healthy, 300-pound male that was relocated because it was becoming a nuisance on a farm more than 30 miles away. Powdermill staff were grateful to have the opportunity to watch as the game wardens sedated and tagged the animal before release. The bear received two ear tags and a lip tattoo for identification. A small milk tooth was extracted which will be used later to determine his age. An infected claw was treated, but otherwise he appeared to be in good health.

Game Wardens arrive at Powdermill
Game Wardens Barron (left) and Harvey (right) arrive at Powdermill with the trap, which is on wheels for easy transport.

The Game Commission estimates the Pennsylvania bear population to be thriving at around 20,000 individuals. Compared to neighboring states, Pennsylvania black bears breed earlier and have more cubs. Bear populations are managed through seasonal harvesting, although only about 2% of those receiving permits are successful hunting a bear. In 2017, the largest bear taken was a 707-pound male from Monroe County!

black bear in Pennsylvania
American black bear. Photo credit: George Pankewytch

Hopefully, this male will find another place to call home, but relocating these animals can be tricky as they have a very good sense of direction and can cover long distances. At this time last year, one radio-collared male walked from Johnstown to Grove City to Pittsburgh, then east along the turnpike and up through the Laurel Highlands and back to Johnstown in about a month.  We give special thanks to the game commission for putting so much effort into maintaining a healthy population of bears that can live in harmony with humans and ensuring that Pennsylvania can continue to be a supportive environment for these spectacular beasts.

Andrea Kautz is a Research Entomologist at Carnegie Museum of Natural History’s Powdermill Nature Reserve. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Before Powdermill Nature Reserve

By Bonnie Isaac

black and white photo of a dirt road and trees

While looking through some images in the archives in the section of Botany I came across this image from July 23, 1923 taken by Gus Link Jr. about 3 miles south of Rector, PA.  There is a good chance that this property later became part of our Powdermill Nature Reserve.

The museum began acquiring properties in 1956 to form Powdermill Nature Reserve. I wonder if the museum folks were out there surveying the area with a nature reserve in mind? What foresight the museum had to acquire properties that have over the past 60 plus years become a beautiful place for research.

In 1923 Gustav Link Jr. was an assistant preparator in Zoology for the natural history museum. Gus Link Jr. worked for the museum from 1912 to 1960.

Bonnie Isaac is the Collection Manager in the Section of Botany. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Powdermill Flood Changes the Landscape

By James Whitacre

Here at Powdermill Nature Reserve, the Carnegie Museum of Natural History’s environmental research center, we were reminded of the ever-present forces of nature when a flood recently inundated the Ligonier Valley. Homes and buildings were damaged and numerous people had to be rescued by swift water rescue crews. At Powdermill, a few of our buildings also experienced damage (see the video at the bottom of this post).

water level chart

On June 20, 2018, over 5.5 inches of rain fell on Powdermill and the surrounding area in about 6 hours. At the nearest USGS stream gauge at Linn Run State Park, the water level rose about four feet in five hours. The force of the flood waters was able to move large boulders, take down trees, and change the course of many streams, including Powdermill Run. The flood levels were so high that we have reason to believe that this was a very significant flood event. But was it a ‘100-year flood’?

The concept of the ‘100-year flood’ is quite familiar, but this concept is a bit misleading. It does not mean that a flood event rated as a ‘100-year flood’ occurs every 100 years. Rather, it means that every year, there is a 1% chance that a flood will reach the annual exceedance probability (AEP) (i.e. the height of the flood waters in a particular area). On average, the AEP will reach that level every 100 years. This definition was established for the National Flood Insurance Program. For more information, see the USGS page The 100-Year Flood—It’s All About Chance.

So the question still stands, was the flood at Powdermill a ‘100-year flood’? Using the power of maps an GPS, the GIS lab at Powdermill decided to compare the FEMA flood zones map to the flood levels observed in the field. As the map shows, it appears that is is very close, though more assessment is needed to be certain.

See the map here.

While the damage was extensive, this event will provide researchers at Powdermill the opportunity to study yet another instance of how natural disasters affect the ecology and landscape of the nature reserve. A similar event six years ago, in June 2012, was when a tornado touched down in the Ligonier Valley and blew down nearly 50 acres of forest in the nature reserve. Powdermill continues to utilize these areas in numerous on-going research projects to track succession and plant-animal interactions after a disturbance. While the flood event may not produce an obvious research project at the moment, Powdermill researchers will be keeping their eyes open to see how we may need to respond.

James Whitacre is the GIS Research Scientist for Carnegie Museum of Natural History, where he primarily manages the GIS Lab at Powdermill Nature Reserve, the Museum’s environmental research center. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Adult Flycatcher

Adult Flycatcher

This adult Flycatcher undergoes the pre-basic molt of the wintering grounds. These adults can be readily identified by their white bars and wear on the feather tips.

Powdermill Nature Reserve’s avian research center is part of Carnegie Museum of Natural History’s biological research station in Rector, Pennsylvania.  The research center operates a bird banding station, conducts bioacoustical research, and performs flight tunnel analysis with the goal of reducing window collisions.

 

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Acadian Flycatcher

acadian flycatcher

This Flycatcher has a pale yellow mouth lining.

Powdermill Nature Reserve’s avian research center is part of Carnegie Museum of Natural History’s biological research station in Rector, Pennsylvania.  The research center operates a bird banding station, conducts bioacoustical research, and performs flight tunnel analysis with the goal of reducing window collisions.