The Nature
Observer’s Journal
The Nature
Observer’s Journal
Transitions:
A Phenological Perspective for August in western Pennsylvania
Chuck Tague
On July 28, 2009 I awoke abruptly to bird song. Outside my open window a Carolina Wren greeted the first light. The wren sang loudly, with gusto -- and solo. He performed his “tea-kettle” crescendos “a cappella” -- unaccompanied by the moderating blend of the avian orchestra: the brassy cardinals, the robins’ flutey woodwinds or a string section of sparrows and finches. Even the percussive woodpeckers were silent.
I got up and drove to Hillman State Park. There I caught a faint, perfume-like whiff of milkweed flowers. I felt an unsettling sadness, an unexplainable loss. Last week the fragrance of milkweed hung heavy across the grasslands. Their colors accented the fields, the wooded edges, every unmowed roadside. The milkweeds’ glory is fading, and it’s fading fast.
Common Milkweed
The salmon blush of the Common Milkweeds’ blossoms looked dull; spent florets hung lifelessly. The glow was missing from Swamp Milkweed flowers. Orange Butterflyweeds looked tarnished, misshapen and sad.
The last of the milkweed flowers were not without attraction. I examined them for butterflies and other pollinators. The Butterflyweeds were a bustling study in orange; orange butterflies and honeybees on clusters of orange blossoms. It was early in the day. The sun had yet to warm the wings of most insects. The first to come to the butterflyweed were Honeybees and Great Spangled Fritillaries.
Honeybee & Butterflyweed
Great Spangled Fritillaries are orange and black butterflies, slightly smaller than a Monarch. They have one flight a year. Males appear first, around the Summer Solstice when the Common Milkweed first blooms. Females eclose from an underground chrysalis a week or two later. During the summer they mate and lay eggs on, or near, violet plants. After the eggs hatch the tiny caterpillars drop and bury themselves in the leaf litter. They will not eat until the violets sprout in spring.
Great Spangled Fritillary on Butterflyweed in early July
The fritillaries at Hillman had been on the wing for a while, some for over a month. They, too, showed the weariness and wear of the season.
As the day warmed activity increased on the Butterflyweed. Pearl Crescents were suddenly abundant. In sharp contrast to the fritillaries, the Pearls were fresh and unblemished. Not much larger than a dime, Pearl Crescents resemble miniature Monarchs. They have three or four flights each year. I witnessed the beginning of the next to last generation of 2009. The last generation would fly in late summer and spend the winter as adults.
Pearl Crescent
The demise of the milkweeds marked the end of the solstice wildflowers but nearby I noticed the first royal-purple tufts of Tall Ironweed. August brings a new set of wildflowers. Teasel was in full bloom and soon thistles would be as well. Tall, pink pyramids of Joe-Pye-Weed were already fully formed. Pearl Crescents would have no shortage of nectar in the next two or three weeks.
Pearl Crescents landed on the Butterflyweed and pumped their wings as they sipped the last of the blossom’s bountiful nectar. I marveled at their impeccable timing. It was not the August wildflowers, however, that interested the Pearl Crescents. In a change that goes unnoticed by all but the Pearls and the most astute botanists, developing asters were filling in spaces abandoned by grasses and the early blooming wildflowers. When the seasons change from summer to fall, when the sun shines over the Equator and the nights are as long as the days, Pennsylvania’s landscape will be dotted and splashed with lilacs, purples and whites. These pastel accents come from the daisy-like flowers of the asters, the host plant of the Pearl Crescent. The middle generation of Pearls feeds on the last of the milkweeds’ nectar then lays its eggs on fresh aster leaves.
A Monarch butterfly glided along the trail, circled without a flap and landed on a milkweed flower. I waited to see if it was an ovipositing female, but it only sipped the milkweed’s nectar then moved on. More Pearl Crescents flitted through the grass. As I admired the butterflies I heard a strange, hiccough-like sound, a Henslow’s Sparrow’s “fish-lip” song. A most-unmusical bird song, it only emphasized that the field birds were as silent as the birds in my neighborhood. The meadowlark, the thrasher, the Yellow Warbler and the Field Sparrow no longer sang.
Juvenile Field Sparrow
I flushed a family of Field Sparrows. A curious juvenile hesitated in a shrub. It checked me out before it scurried to join its parents. The birds were also in a period of transition. Some bird species, like the Henslow’s Sparrow and the Carolina Wren will raise one more brood. Most birds, however, are preparing for winter. They are using the lazy midsummer days, the days with an abundance of sunlight and food, and no reproductive responsibilities, to molt into a new plumage and fatten up for their journey south. Young birds must quickly gain the experience they’ll need to survive.
After I left Hillman I stopped at the pond at Bald Knob. Solitary Sandpipers and Greater and Lesser Yellowlegs fed along the margins of ponds. Families of Killdeer gathered to form flocks. Yellow Warblers have disappeared. Some songbirds and shorebirds have already begun their journey.
It’s August, the month of transition. August begins at the height of summer; when August ends, fall is in the air. What transitions can an observer expect in the first half of the month?
Expect a change in wildflowers. Now’s the time to visit Jennings Prairie to see the Blazing Star. Here’s a link to the Nature Observer’s checklist of wildflowers that bloom in early August.
Blazing Star, “Liatris spicata”
Look along stream banks for Cardinal Flower. Their appearance indicates the Ruby-throated Hummingbird migration is about to begin.
Cardinal Flower, “Lobelia cardinalis”
Look for an influx of southern butterflies and dragonflies. These are insects that are ill-equipped to survive northern winters, yet they expand their range northward in summer. These emigrations are difficult to predict. They vary in distance and numbers each year. In some species there may be no movement at all one year, then huge numbers on the wing the following year.
Southern (non-wintering) Butterflies that immigrate to western Pennsylvania
Zebra Swallowtail, “Eurytides marcellus” (Host plant: Pawpaw)
Giant Swallowtail, “Papillo cresphontes” (Hop-tree and Prickly-ash)
Cloudless Sulphur, “Phoebis sennae” (Sennas and other plants in the pea family))
Little Yellow, “Eurema lisa” (herbs in the pea family)
Sleepy Orange, “E. nicippe” (shrubs in the pea family)
Variegated Fritillary, “Euptoieta claudia” (violets)
American Lady, “Vanessa virginiensis” (everlastings and cudweeds)
Painted Lady, “V. cardui” (thistles)
Red Admiral, “V. atalanta” (nettle)
Common Buckeye, “Junonia coenia” (a variety of low-growing herbs, especially plantains)
Common Checkered-Skipper, “Pyrgus. communis” (mallows)
Fiery Skipper, “Hylephila phyleus” (grasses)
Sachem, Atalopedes campestris” (grasses)
Click here for a photographic guide to southern butterflies that show up in western Pennsylvania.
Northern Wild Senna, “Senna hebacarpa”
On July 28, I discovered a patch of Northern Wild Senna, Senna hebacarpa at Hillman State Park, a plant that I’d never seen there before. Note the peculiar fuzzy fuzzy ovaries. I will check these plants often in August. It’s the host to Cloudless Sulphurs and Sleepy Orange butterflies.
Carolina Saddlebags
Also on July 28, I photographed this southern dragonfly, a Carolina Saddlebags, at Hillman State Park. It’s not just birds and butterflies that move with the seasons.
After a dry early summer, western Pennsylvania has been getting steady and frequent rain. The forests are lush and streams are flowing. The rain should bring out mushrooms and wandering salamanders. The orange Chicken-of-the-woods, is a tasty and easily identified edible.
Chicken-of-the-woods
Don’t be fooled. Jack-o-lanterns are not!
Jack-o-lanterns
Be aware. You could see a bear! In late summer Black Bears are moving around. This is the time I most often see them.
Migrating flocks of Common Nighthawks will soon gather in and around the river valleys, as they fatten up on evening flying insects before they resume their incredible journey to South America.
Growing flocks of Chimney Swifts are chattering and chasing each other over the city rooftops.
Shorebird migration always brings surprises. With water levels fluctuating, it could be a good year for these long-distance migrants in western Pennsylvania. Check along any exposed sand or gravel bars and dry margins of rivers, lakes, even farm ponds. Don’t forget to check wet meadows and flooded fields. The pace of shorebird migration will increase into September.
More and more molted feathers will drop to the ground. Recently shed turkey feathers litter the trail, Canada Goose feathers the wetlands.
Young birds and mammals are learning their world. Expect the unexpected, like this Green Heron.
Green Heron
As August progresses, keep an eye out for migrating songbirds - especially warblers. When the breeding season ends songbirds concentrate on fattening up for their long migration to the tropics. Even though their populations have swollen with this year’s young, the birds are quiet and hard to find. Listen for the "chip - chip" of their contact calls as they hunt for caterpillars in the treetops.
Most songbirds migrate at night and you can hear their chips overhead as they pass through the darkness.
Songbirds are not the only reason to go out after dark. Fireflies and katydids alone are worth staying up for. The Perseid Meteor Shower peaks on August 12 but any time after midnight in the week before and after should produce shooting stars.
What’s new in the night sky? The latest addition to the International Space Station, an array of solar panels, increased it visibility. It is now the brightest object in the sky except for the Sun and Moon. The ISS orbits 220 miles above Earth, so it is only visible just after sundown or before sunrise. It cannot be seen from Pittsburgh during the first week of August but NASA posts dates and times at this site:
http://spaceflight.nasa.gov/realdata/sightings
Caterpillars are more visible in August. The silky nests of Fall Webworms encase parts of trees from sections of branches to whole saplings. I saw a Wooly Bear the other day. The first of the Hickory Tussock Moths are crawling about.
Hickory Tussock Moth caterpillar
The Yellow-collared Scape Moth is a colorful day-flyer that hangs out on late summer wildflowers. It can easily be mistaken for a Firefly.
Yellow-collared Scape Moth
Katydids will soon be calling. I heard my first cicada on July 28.
Fruits are developing on trees and shrubs in the forest. Witch Hazel capsules are plentiful. Beechnuts are forming. What will the acorn crop be like?
Red Oak acorns, Mt. Davis, PA July 16, 2009
The seasons are changing. There’s never a better time to get out and explore.
Monday, August 1, 2011