The Nature of Delaware

By Robert Fisher, Abbott’s Mill Nature Center Intern

Southern Delaware’s lingering drought received a brief respite on July 19th.  At 2pm severe thunderstorms rolled into the Milford area, bringing heavy rainfall. This steady inundation brought much needed moisture to stressed plants. While the rain was a blessing for most plants, the storm’s associated lightning and wind had a dramatic effect on some of the Milford Millpond Nature Preserve’s  trees.

This Tulip Tree was struck by lightning during the July 19th storm.

Abbott’s Mill naturalists prepping for a Native American program in the Lindale Tract encountered an abundance of tree debris and also discovered an impressive lightning strike on a large tulip tree (Liriodendron tulipfera), also known as yellow poplar.  The trees appears to have survived, but it will bear the marks of the strike for the rest of its days.

Path of the lightning through the tree.

The long scar, which runs the length of this impressive tree, tells us about lightning attraction and how trees handle it.  Tulip trees, being one of the tallest and fastest growing hardwood species in the eastern United States, have a  high biomass.  The combination of height and girth make these trees excellent conductors of lightning in the forest.  However, sap is a poor conductor and in a lightning strike, is superheated, becoming steam.  From this rapid expansion of liquid to a gas, an explosion occurs. The photo below shows fragments of bark and sapwood blown off of the tree, accounting for the exposed wood.  Shards of wood were found over 50′ from the tree and throughout the sub-canopy forest layer.

Debris from the strike covers the surrounding area.

The high visibility location of this tulip tree on the Lindale Loop Trail will serve as a teaching point for years to come.  If you are interested in seeing the tree for yourself, stop by Abbott’s Mill Nature Center and pick up a trail map highlighting our miles of hiking trails.  However, you might want to check out the chance of thunderstorms in the area before you venture afield!

Shard of the tree spiked in the ground.

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By Derek Stoner, Conservation Project Coordinator

A "flock" of Tiger Swallowtails descends upon the Joe Pye Weed blooms at Ashland Nature Center. Image by Derek Stoner, July 28, 2011.

Every summer a showy spectacle takes place in the corner of the Ashland Nature Center parking lot, right beside the recycling center.  The blooming of the Joe Pye Weed attracts large butterflies in large numbers.  By large butterflies, I mean the big and beautiful swallowtails.  In this case, the predominant swallowtail is the Eastern Tiger Swallowtail, which happens to be the official state butterfly of Delaware.

This morning I counted 14 Tiger Swallowtails enjoying the nectar at the pink Joe Pye flowers.  The highest number I’ve recorded at this patch is 47 swallowtails at once, also in late July several years ago.   It is interesting to watch these colorful insects  joust for the best nectar sources on the Joe Pye, with multiple butterflies sometimes perched on one flower.

A gorgeous Pipevine Swallowtail nectaring on mint at Middle Run Natural Area. Image by Derek Stoner, July 28, 2011.

Butterfly populations are “bumping” up now, with many species being seen in strong numbers and good reports coming in from the field.  These sightings bode well for this Saturday’s North America Butterfly Count– join us in the Ashland parking lot at 9:30am or 1:00pm on Saturday, July 30, to take part in this fun citizen sceince event!

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By Joe Sebastiani, Seasonal Program Team Leader

If we could send a cool breeze through your computer screen this week, we would.  Nature is adapting to the hot conditions outdoors at Ashland these days through a number of means.  For instance, I took a quick walk by a small creek yesterday and spooked up a huge number of Gray Catbirds and American Robins that were bathing and taking advantage of the cooler micro-climate.  If you see a bird in your yard on a hot day, take a look…it might be panting like a dog.  Other animals like White-tailed Deer and Red Fox become very nocturnal.  Birds like a Red-tailed Hawk might take a flight into high altitudes to cool off. 

Here are a few photos from a colder season to help you deal with the heat this week.  I will still take summertime!

Delaware Nature Society Teen Naturalists after a hike to The Pinnacle in the Pennsylvania Appalachian Mountains a few years back.

Remember the days when we had to snowshoe in order to take a hike at Ashland?

Maybe you are wishing you were freezing in Nebraska...like we did on our trip there in March, 2009.

How about a December birding trip to the Delaware City Waterfront, complete with sideways icicles?

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By Derek Stoner, Conservation Project Coordinator

A Regal Fritillary sips nectar from a Butterflyweed at Fort Indiantown Gap. Image by Derek Stoner, July 1, 2011.

On July 1, the Delaware Nature Society led another trip up to Fort Indiantown Gap in Lebanon County, Pennsylvania, to take part in the wildly popular tour of this military base’s unique population of Regal Fritillaries.  Each year in July, these beautiful butterflies are on the wing as they seek mates amidst the wildflowers on this intensively-managed property.  During our trip, we saw at least two dozen of these rare butterflies that are known for looking like a “Monarch butterfly dipped in chocolate.”

A pair of Black Swallowtails mating at Fort Indiantown Gap. Image by Derek Stoner, July 1, 2011.

The middle of summer brings about peak conditions for butterflies: plenty of nectar sources for feeding adults and plenty of food sources (plant leaves) for feeding larva.  Adult butterflies have a very short lifespan (two to four weeks on average) and the summer season is full of butterfly mating activity as these insects seek to continue the next generation of their kind.

On Saturday, July 30, the Delaware Nature Society will be taking part in the annual North America Butterfly Count .  This count takes place in the month of July on a date selected by a regional compiler of this citizen science effort.  The North Delaware count on July 30 will include two Delaware Nature Society properties: Ashland and Coverdale Farm Preserve.  We often tally 25-30 species of butterflies during the day, and enjoy other great sights besides the beautiful butterflies.

For the count at Ashland we will meet at 9:30am in the parking lot. To join us in the afternoon count at Coverdale, we will meet at the Ashland parking lot at 1:00pm.  Please contact me if you plan to participate.  Thanks! 

- Derek Stoner, derek@delawarenaturesociety.org

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By Joe Sebastiani, Seasonal Program Team Leader

In 1995, a male box turtle was found at Ashland Nature Center and marked by Jim White.   It was caught again at Ashland on July 16, 2010 and released with a transmitter attached to its shell.  This was done so that any time of year, we can track him with radio-telemtry equipment to study his movements.  He spends his time in a thicket near the bat box along the succession trail.  His home range is only about 1-acre in size.  See “Shell Slueths and a Box Turtle” for the story from last year. 

Since July 16, 2010, we have relocated this turtle 4 times.  The last time it was found was September 1, 2010 and he weighed 480 grams (including the transmitter).  Our education interns tried several times over the fall and spring to find him but were unsuccessful.  Usually the turtle stays in very thick poison ivy and blackberry thickets, making him very difficult to locate.  Today I searched for him so that our Shell Slueths and Creepy Crawly Scientists summer camps could measure and weigh him, and see where he lives.  I got lucky and found him in his favorite place…poison ivy and impenetrable blackberry thickets.  Fortunately, he was on the edge and I didn’t have to get scraped up by blackberry bushes or spend the weekend bathing in calamine lotion.

A camper uses the radio telemetry equipment to hear the beeps coming from the turtle transmitter.

The box turtle weighed 495 grams, so he gained a little weight since last September.  We counted the rings on one of the scutes (scales) on the shell, and found that the turtle is at least 21 years old (he can legally drink). 

This is the transmitter that the box turtle has on his shell. It can be taken off at any time and it does not hurt the turtle. The battery lasts five years, so we will be tracking him for a few more seasons.

Campers help with the "weigh in". We found that this turtle is at a healthy weight for a male box turtle at this time of year.

According to Jim and Amy White, authors of Amphibians and Reptiles of Delmarva, populations of this species are in decline due to several factors including habitat loss and fragmentation, and death from motor vehicles and lawnmowers, plus overcollection for the pet trade.  If you find a box turtle, leave it in its habitat.  Do not take it home as a pet or move it to a new location.  These long-lived animals are important components of the local ecosystem, so do your part and leave them in their habitat.  As we know from this turtle, their home range might only be an acre or two in size.

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