Natural Events


  • The beginning of fall triggers the migration of warblers, vireos, thrushes, and other songbirds to their tropical winter destinations -- Mexico, Central America, South America, and the Caribbean Islands.

  • As September continues, the raptors join the migrating birds. Thousands of broad-winged hawks, eagles, and other birds of prey head south for the winter.

  • Monarch butterflies begin their long migration to Mexico.  These insects may cover up to 80 miles per day, traveling 10-30 mph, as they float on the breezes.

  • By the end of September, the fall wildflowers have started to bloom.  Beautiful gold, white, and purple flowers bloom on asters, goldenrods, sunflowers, and daisies.


  • With winter migration and hibernation approaching, animals compete for the high fat and carbohydrate concentrations of berries and nuts.  

  • Cooler temperatures and shorter days cause the green chlorophyll to disappear from deciduous leaves, allowing for bright, colorful pigments to emerge.

  • Snakes, turtles, frogs, and salamanders sound their retreat during the month of October.  Retreating to underground dens, these animals have adapted to the cold of winter by entering a state of dormancy or suspended animation.

  • At the end of October, over 30 species of waterfowl begin to migrate south.  Listen and look for Canada geese flying in a “V” formation that decreases wind resistance for the entire flock.


  • The largest raptos round up the fall migration.  Northern harriers, goshawks, red-tailed hawks, red-shouldered hawks, and turkey vultures fly south for the winter.

  • After the fall leaves have fallen to the ground, billions of microorganisms, earthworms, sow bugs, and millipedes feed on the fallen leaves. Nutrients are returned to the soil through their droppings.  

  • During third week of November, the white-tailed deer breeds.  They give birth in May or June, often to twins.  The white-tailed deer is the state mammal of Pennsylvania.  

  • During the last week of November, birds from Canada migrate to our area for the winter.  Look for purple finches, evening grosbeaks, fox sparrows, and tree sparrows at your feeders.

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PEEC Events

View our Calendar page to see programs available at PEEC during the autumn season.

Natural Events


  • During the first week of June, look for painted turtles and snapping turtles that have left the water to dig their nests and lay eggs.  Many of the eggs are dug up by predators.
  • Mountain laurel blooms of pink and white flowers appear in the well-drained soils of woodlands, just before the beginning of summer.  This flower was chosen to be Pennsylvania’s state flower in 1933.  
  • Male song birds are actively singing throughout June.  Their songs are used to establish territories and attract mates.  
  • There are 20 species of firefly (a.k.a. lightning bug) and their average lifespan is only one week.  Female fireflies do not fly, but produce light to attract mates.


  • In the beginning of July, butterflies emerge from their chrysalises to eat the sweet nectar of summer wildflowers.  Butterflies bask in the sunshine because their bodies need to be at least 80ºF to fly.
  • As July progresses, gypsy moths begin to emerge from their brown pupae.  Only male gypsy moths fly because the females are too heavy with eggs.  The females attract males by secreting pheromones.
  • Look for blueberries, huckleberries, raspberries, blackberries, and dewberries. These bushes are low growing and accessible to wildlife, making their seeds easily dispersed.
  • As July ends, the chorus of cicadas, grasshoppers, crickets, and katydids can be heard.  The songs are produced by the rubbing and vibrating of wings and legs. Like most noises in nature, the calls attract mates and establish territories.


  • As summer comes to a close, millions of shorebirds head south.  Over twenty different species pass through our region during the fall migration, including the solitary sandpiper.
  • The second week of August begins the season of the spiders.  Look for webs in the fields and forests as many different spider species mate and lay eggs.  In the ponds, fishing spiders are active, preying on tadpoles, salamanders, and very small fish.
  • Search for mushrooms after a late summer rain.  Enjoy the diversity, but do not eat them unless a professional has properly identified them as being edible. Many species are toxic.  
  • During the last week of August, over twenty different species of snakes give birth.  Baby snakes are completely independent at birth.  As summer comes to an end, they must find a place to hibernate.  Many snakes will hibernate together in one den.

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PEEC Events

View our Calendar Page to see programs available at PEEC during the summer season.


Seasonal Highlights

A Sense of Place…
“There is a great deal of talk these days about saving the environment.  We must…for the environment sustains our bodies.  But as humans we also require support for our spirits … and this is what certain kinds of places provide.

The catalyst that converts any physical location – any environment if you will – into a place, is the process of experiencing deeply.  A place is a piece of the whole environment that has been claimed by feelings.  Viewed simply as a resource that sustains our humanity, the earth is a collection of places.

We never speak, for example, of an environment we have known; it is always places we have known- and recall.  We are homesick for places, we are reminded of places.  It is the sounds, the smells and sights of places which haunt us against which we often measure our present"

Alan Gussow

At PEEC, our environment and all that it provides is driven by nature and natural systems, celebrating all of the celestial seasons.  Opportunities for experiencing profound learning and connecting are offered all year long. Nature’s calendar designs our calendar.

Read a little more about the Summer Solstice, Autumnal Equinox, Winter Solstice and Vernal Equinox and then celebrate the seasons…celebrate the diversity:

  • Naturally – in what you see, hear, smell, touch and taste
  • Celestially – in what you can imagine
  • Actively – in what you can do at PEEC
  • Sustainably - in what you can do (simply) to sustain and conserve

Vernal Equinox - March through May

Every year, around March 20, the sun is directly over the equator, causing night and day to be roughly the same length. The vernal equinox also signals the first day of spring.

Summer Solstice - June through August

Yearly, around June 21, the sun lingers longer than any other day of the year.  Since this is the longest day, it is the shortest night. The end of June signals the beginning of summer and the days begin to get gradually shorter.

Autumnal Equinox - September through November

Once again the sun is directly over the equator, and night and day are again roughly the same length.  Fall is here, the trees are turning, and the birds are beginning to leave for their wintering grounds.  Winter is right around the corner.

Winter Solstice - December through February

Every year, around December 22, winter officially begins.   The winter solstice marks the shortest day of the year …or the longest night of the year…when the sun is furthest south in sky.  As the days gradually get longer, we remember that spring is on its way again.


Thank you to all photographers who have graciously agreed to allow us to use their photos on our website:

John Barclay
Eli Rivera
Heather Chadwick
Maria Schramm
James Maloney
Jennifer Loven
Alex Westner
Clay Spencer
Richard Frear
M. Woodbridge Williams
Don F. Mitchison
Office of Sustainability, Princeton University


Additional information