Sunday, August 01, 2010

Skippers at Griggstown Grasslands

Yesterday I visited Griggstown Grasslands Preserve, a large native meadow maintained by the local township. Provided that the property is mowed on an appropriate schedule, the preserve can be productive throughout the year.  Most birds have stopped singing by now. One of the few still singing was a beautiful male Indigo Bunting. Other birds included Tree and Barn Swallows, Great-crested Flycatchers, a Willow Flycatcher, and juvenile Field Sparrows.

At this time of year I usually spend more time looking for insects than birds. There were a lot of butterflies active, though not quite as many as I expected. In one small patches I found three species of skippers. Skippers are small butterflies that are usually grouped within their own superfamily separate from true butterflies like swallowtails and brushfoots. Skippers have slightly different tips on their antennae; while true butterflies have a simple knobbed tip, skipper antennae have a knob that curves outward. One of the most common summer skippers in this area is the Zabulon Skipper (Poanes zabulon), pictured in the two images above.

This second species is a Least Skipper (Ancyloxypha numitor). As the name implies, this species is tiny, even for a skipper. It flutters close to the ground so it could be easily missed.

The third is a Swarthy Skipper (Nastra lherminier), a new species for me. Like the Least Skipper, this species is very small and seems to stay low. It also looks very dull. In fact, Brock and Kaufman suggest its dullness as a field mark in their description:
Above dark brown, rarely with a trace of forewing spots. Below hindwing yellow-brown with veins slightly paler. In most of its range, few other skippers are so dull.
While I do not see much trace of yellow in the hindwings of this individual, the other elements of the description fit.

In addition to the skippers, I saw a lot of dragonflies flying around. Unfortunately few of them stopped long enough for me to get a photo or take a good look at them.