Photo by Corey Husic

Thursday, August 11, 2011

The First Signs of Fall?

It is not even mid-August, but I have already noticed a murmuration of starlings (actually I have seen a few).  Witnessing these roving bands is to me one of the earliest signs that summer is beginning to wane.  I suspect that this is, in part, because the observation coincides with the time that I begin working on (or at least thinking about) the syllabi for my fall courses.  Fall is my favorite season, but I always experience a touch of melancholy when I notice signs of summer’s end.

Meteorological summer ends with the month of August, although many people associate the season's passing with Labor Day weekend since beaches and pools typically close.  Our days have been getting shorter for some time now, and the third week of July that is typically the hottest in eastern PA is long gone.  You can feel the fresher, cooler air if you are an early riser and it is refreshing to open the windows in the evening.  And there are other signs that things in nature are starting to change. The complementary colors of fall-blooming flowers—purple and gold—are already visible in the Joe Pye Weed, Ironweed, and the species of Goldenrod that are already blooming.  And any birders out there know that the hawk watch seasons at Bake Oven Knob ( and Hawk Mountain ( commence in just a few days on August 15th.

What do all of these seasonal notes tell us?  That it is time to think about fall phenology and to contribute new data to the Eastern PA Phenology Project (! 
There are a number of raptors that will begin to migrate early including Bald Eagles and Ospreys.  Songbirds that are early fall migrants include Louisiana Waterthrush, Yellow-billed Cuckoos, and flycatchers--especially Eastern Kingbird, Olive-sided Flycatcher, and Empidonax species (the ones I can’t typically distinguish without hearing their spring songs).  In fact, late this afternoon, a Least Flycatcher was spotted by my son in an apple tree by our house.

You should begin to see Monarch caterpillars and chrysalises soon.  This past week, I have been seeing more Monarchs nectaring on plants, but, as of yet, they aren’t showing migration behavior.  These butterflies will likely lay eggs and you may soon begin to see the caterpillars munching on milkweed.

Yesterday we began seeing the dark form of the female Eastern Tiger Swallowtail that mimics the Pipevine Swallowtail—both being late season butterflies in this region.

Below is a list of some other fall seasonal signs to be looking for.  Don’t forget to report your observations of seasonal changes to the Eastern PA Phenology Project at

Goldenrod (Solidago sp.; photo by D. Husic)

Aromatic Aster (Symphyotrichum oblongifolius; photo by D. Husic)
-         First blooms on goldenrod (Solidago sp.) and asters (typically Symphyotrichum sp. in this region);

-         Chipmunks collecting and storing food;

-         Milkweed seed pods opening and dispersal of the seeds;

-         Last sightings of Barn and Tree Swallows (see fact sheets on project website for identification);

-         First sightings of Dark-eyed Juncos returning – often at feeders;

-         Loss of bright yellow color on male American Goldfinches or of the brilliant blue of Indigo Buntings;

-         The date of the first frost;

-         Tree leaves beginning to change color (note species, first color changes, timing of tree at peak color).  The Red Maple is one of our species of particular interest, but we will take reports on any and all trees that are common to eastern PA (see fact sheet on project website);

-         The timing of when leaves begin to fall and when a tree is completely bare; 

-         The timing of sumac leaves changing color and loosing leaves; 

-         Starting this fall, we are particularly interested comparing the timing of when native vs. invasive shrubs lose all of their leaves.  Some examples include native viburnums, dogwoods, and blueberries, vs. the invasive Autumn Olive, Multiflora Rose, Japanese Honeysuckle, and Japanese Barberry.
-         Last sightings of Bumblebee, Cabbage Whites or Ruby-throated Hummingbird (see fact sheets on project website for identification); 

-         First sighting of a Milbert’s Tortoiseshell butterfly; 

Milbert's Tortoiseshell (Aglais milberti; photo by Corey Husic)
-         The timing of the emergence of the yellow flowers on Witch-hazel (picture on fact sheet on project website). 

These are just some of the fall seasonal signs.  If you observe other phenological events, we would love to know about your observations.  Remember that you can report your observations at  Periodic summaries of what our project contributors are observing will be posted on this blog.

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