Tuesday, July 19, 2011

Summer strategy

It can be tough to bird in the summer, what with the obscuring leaves on the trees and a relative paucity of birdsong compared to spring and fall.  The strain on my neck from craning after treetop birds doesn't always seem worth the number of species I usually get this time of year.  So on many summer hikes I focus on the lower levels of the forest instead. This is also a good idea when taking a walk with a non-birding friend, e.g. my husband.  He’s tolerant of my being a nature geek when we hike together, but real birding with its stops and starts, and its long periods of watching a treetop in hopes that the tanager/warbler/whatever will pop into sight, would probably try his patience.

"I'm sure there's an oriole in there somewhere!"

I put this theory to work last week when we had some wonderfully cool weather (highs in the mid 80s rather than mid 90s or above) and Victor and I took a short hike along the C&O canal. I'll admit I still had to pull myself away from a few tantalizingly hidden birds, but there was so much else going on in the forest, I didn't feel I was missing out.

Milepost markers dot the trail.

It was a joy to be able to hike in the peak of summer without being soaked in sweat.  Even the black vultures were out enjoying the sunshine.  We found several of them basking in the parking lot with their wings opened, reminiscent of cormorants. I thought they looked very gawky and silly, but it must have been comfortable for all of them to be doing it.

I often see black vultures when I hike the C&O, but not usually like this!

Once we started the trail, we found that any sunny, still spot in the canal was covered with duckweed, and so were most of the turtles who’d hauled themselves onto logs to bask in the sunshine.

Turtles, fish, ducks, and even beaver may eat duckweed.

Also enjoying the canal was a green heron perched on a branch just above the duckweed-covered surface. We spotted it there when we walked upstream, and it was still there when we came back, taking advantage of a great fishing spot.  Periodically it would stretch forward, balance there for a while, then lightning fast snake its head down and snatch a minnow from the surface.  Yum!



The air was full of insect life.  Tiny beetles and bees swarmed any wildflowers, and dragonflies darted along the trail hunting them. We saw Eastern Amberwings and male (slate blue) and female (grass green) Eastern Pondhawks.  While photographing a perched female Pondhawk I also discovered a tiny Green Treefrog motionless on a nearby leaf.  Despite my inadvertently jostling its branch a couple times, the frog never even blinked.  It was very well camouflaged; I would have been completely unaware had it not been for the dragonfly perching a few inches away.

This female Pondhawk was amazingly tolerant of me.

You don't see me...

Butterflies including Tiger Swallowtails, Northern Pearly-eyes and Zebra Swallowtails flitted along the trail as well. Paw-paw trees make up much of the forest understory along the C & O; since their leaves are the only thing that Zebra Swallowtail caterpillars eat, you won’t see the black and white butterflies without them around. Talk about your picky eaters! 

A mud-puddling Tiger Swallowtail
Looks like this Pearly-eye lost a few bits of wing to a hungry predator.

Zebra Swallowtails sport fashionable red antennae.

The paw-paw fruit won't be ripe until late August.

We also found a tree with nearly twenty cocoons where caterpillars had rolled leaves around themselves.  I didn’t want to disturb their metamorphosis, so I didn’t unroll any. Thus I may never know what species of caterpillar this was. From the size (roughly half-inch diameter at the widest end) I’m guessing one of our large silkworm moths, maybe Promethea or Polyphemus. I managed to get one photo looking straight into the cocoon, with a just-distinguishable face looking out. Does anybody recognize what these were? I’d sure love to know. I’m kind of wishing I had unrolled one just a little to see what was inside. Please leave a comment if you think you know what they were.

Mystery pupa

Go away, I'm busy!

Last but not least, we saw several gorgeous spiderwebs beside the trail, some in the process of being rebuilt.  All belonged to a kind of orb spider called Arrow-shaped Micrathena. They rebuild at least some of their web every day, typical for orb spiders. They’re nowhere close to the size of the Golden-silk spiders we saw in Florida; instead these little guys were only about a quarter of an inch big.  Their shape however is pretty interesting: their abdomen is a bulgy triangle with little spikes.  We watched one spider who’d only completed about five of its outer spirals so far, and was busily spinning the rest.  Apparently they always leave a hole at the center of their web so they can easily switch back and forth between sides.  I suppose that could provide protection against flying predators who want to snatch them right off the web, or it could allow the spider to reach its own newly-snagged prey more quickly.  Pretty clever!

Each circuit took about twenty seconds to make.

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