New England aster with rigid leaf goldenrod

September phenology

Holy Wisdom MonasteryCare for the Earth, Friends of Wisdom Prairie, Phenology Leave a Comment

by Sylvia Marek

New England aster with rigid leaf goldenrod

New England aster with rigid leaf goldenrod

Phenology is a science focused on observing and recording biological events from year to year and their relationships to the change of seasons and climate.

These are the “normal” phenology events we expect to see here and in the Madison area this month. We would love to hear about what you are seeing on the grounds of Holy Wisdom Monastery. Please comment on this post with what you are observing, where at Holy Wisdom and the date you observed the event.

September Phenology

The following September phenology is from my phenology notebooks. These phenomena do not occur at the same time every year. Some can be earlier or later, depending on temperature, wind, precipitation and location of observation.

  • Thirteen hours of daylight in early September, 11.5 hours at the end of the month
  • First weeks in September seem like summer, last few like autumn.
  • Autumnal equinox, September 22 or 23
  • Harvest moon visible in the sky longer than other moons
  • Frost possible end of September
  • Birds, monarchs, dragonflies, bats and salamanders continue to migrate
  • Many insects are active
  • Asters, goldenrods, gentians, sunflowers, lady’s-tresses, orchids and other flowers bloom
  • Fall color


  • Fall migration is a good time to watch birds although identification can be challenging
  • Breeding season is over and robins, bluebirds, blackbirds, goldfinches, and mixed flocks of warblers, vireos and flycatchers gather to feast on insects, seeds and fruits
  • Most birds that nest in the far north or temperate zones and winter in the tropics migrate at night when there is a north wind or it is calm. Listen for their sweet “seep, cheep, chirp” call notes as they fly overhead.
  • My notes indicate warbler migration (about 25 species) usually begins mid-August, peaks in mid-September and continues through the end of the month
  • Look for flocks of yellow-rumped and palm warblers especially in late September. Also, a few orange-crowned
  • Soaring birds migrate by day. Look for hawks, swallows, pelicans and cranes.
  • Broad-winged hawks are one of the first hawk species to migrate. Look for “kettles” or flocks of them. Late flocks of chimney swifts and swallows continue to head south. They’re usually gone by the end of the month
  • Nighthawks continue to migrate, especially in early evening.
  • Shorebirds started passing through our area in July and usually reach their peak in September
  • Some ducks show up. Lesser scaup, blue-wing and green-wing teal, ring-necked duck, red-breasted merganser and northern pintail
  • Most hummingbirds leave by the end of the month. (I have observed ruby-throated as late as October 9)
  • Red-breasted nuthatches arrive in more numbers some years
  • Flocks of white-throated and white-crowned sparrows arrive mid-September
  • First dark-eyed juncos, American tree sparrows, pine siskins and brown creepers show up end of September. Many will spend the winter.
  • Look for golden-crowned and ruby-crowned kinglets
  • Barred, great horned and screech owls are very vocal and give territorial calls
  • Young owls leave their parents. This natal dispersal is caused by a change in hormones


  • Male white-tailed deer shed velvet and polish antlers on tree trunks
  • Deer molt summer red coats and grow new thick gray or brown fur for winter
  • Chipmunks, squirrels, and mice harvest and store nuts and seeds
  • Little brown bats migrate by the end of September


  • Monarch migration continues to increase during the first part of the month. Look for monarchs nectaring on flowers during the day. In the evening large clusters gather and roost on trees for the night. They continue on their journey to Mexico where they will spend the winter
  • Other butterflies to look for include yellow and black swallowtails, red admiral, mourning cloak, painted lady, lots of clouded and alfalfa sulphers and common or cabbage whites
  • Many moth species are active. Sphinx moth species include hummingbird, bumblebee and white-lined
  • Woolly-bear caterpillars (Isabella moth) are common
  • Almost every September I find a large brown pandorus sphinx moth caterpillar on Virginia creeper or grapevine
  • Green darner dragonflies (Anax Junius) gather in great numbers before migrating south for the winter
  • Look for large numbers of small red-bodied dragonflies or meadowhawks (Sympetrium species), especially on lawns. The autumn meadowhawk is probably the last dragonfly to be seen in fall
  • Crickets, long-horned and short-horned grasshoppers continue to call day and night when temperatures are above 55 degrees
  • Snowy tree crickets now call day and night. Count the number of chirps in 14 seconds and add 40 to find out the temperature
  • Cicadas buzz on warm days
  • Increase in some species of hornets and wasps and bees
  • Winged ants disperse. Queens set up new colonies
  • Box elder bugs and Asian ladybugs (beetles) are very numerous
  • Look for insects on goldenrods (soldier beetles, ambush bugs, assassin bugs, aphids, lacewings, leafhoppers, flies…)
  • I have records of finding a few last fireflies and dogbane beetles
  • Japanese beetle numbers dwindle
  • Mosquitoes, ticks and biting flies continue to be annoying. Take precaution.


  • The webs of orb weavers are lovely when covered with sparkling dew
  • Cute crab spiders can be found on goldenrods and thistles
  • Look for “ballooning” spiderlings. Newly hatched spiders climb to the tops of vegetation and spin strands of silk that are caught by the wind. Then the little spiders float through the air to a new area


  • Month of blooming asters, goldenrods, gentians, sunflowers and lady’s-tresses orchids
  • Asters: sky-blue, smooth, New England, frost, calico, shining, panicled, stiff, aromatic or fall, silky, heath, red-stem, short’s, arrow-leaved and crooked stem
  • Goldenrods: stiff, Dyer’s weed, Riddell’s, Canada, showy, Missouri, and in woodlands; zig-zag and elm-leaved
  • Gentians: bottle, stiff, fringed, downy and creamy
  • Sunflowers: sawtooth, tall, showy and woodland
  • Orchids: Great Plain’s lady’s-tresses orchids (Spiranthes Magnicarpa), slender (S. lacera) and nodding (S. cernua), lady’s-tresses
  • Also in bloom: great lobelia, thistle, turtlehead, white snakeroot, blazing star, Rudbeckia species, vervain, obedient plant, harebell and smartweeds
  • I have found violets and dandelions in bloom in September

Seeds and Colorful Fruits

  • Abundant and consumed by birds and mammals
  • Most grasses have finished blooming and have produced seeds (grains). Big bluestem, little bluestem, Indian, switch, cord, blue-joint, side-oats grama, prairie dropseed, hairy grama, bottlebrush, June, fall and purple love grass
  • Seeds disperse in different ways.
    • Drifters – milkweed pods open and release brown seeds attached to fluffy white “silk.” Thistle “down.”
    • Hitch hikers – tick trefoils, beggar’s-ticks, burdock, enchanter’s nightshade, agrimony, white avens, stickseed, honewort
    • Shooters – jewelweed, jumpseed
  • Red, blue, purple and white fruits disappear quickly

Fall Color

  • Prairie grasses turn fall colors: tan, golden yellow, orange, red, pinkish, bluish and purple
  • Little bluestem turns reddish to bronzy orange and is adorned with fluffy silvery seeds
  • Autumn color of flowering spurge is orangish-red and quite showy
  • Although some leaves started to turn color in August, more turn during the month
  • Red and orange: (especially in sunny areas) sumac, woodbine, gray, red osier, and pagoda dogwoods, poison-ivy, viburnums, red and sugar maples
  • Yellow: black and honey locust, butternut, walnut, basswood, ash, birch, box elder, aspen, sugar maple
  • Brown: inner needles of white pine and arborvitae turn brown and fall


  • Look for puffballs, shaggy mane, meadow, bolete, russula, chanterelle, fairy ring and other marasmius, stinkhorn, bird’s nest fungi, earth star, suphur polyporus, bitter panellus and jack-o-lantern (both glow in the dark), coral fungus and more


  • Salamanders leave ponds and migrate to woodlands during warm moist nights usually in mid-September (they will spend the winter in the woodlands)
  • Chorus frogs, spring peepers and tree frogs occasionally call and begin to look for winter hibernating spots usually in wooded areas under leaf litter
  • Look for plant galls

Sylvia Marek is a highly trained and experienced naturalist. She works for the University of Wisconsin Arboretum and is a first rate birder.

Please share the biological events you notice while at Holy Wisdom Monastery below (remember to include what you see, where and when).

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