Astronomy

Early in the morning on Wednesday the 17th and Thursday the 18th look for the bright planets Venus and Jupiter to either side of the crescent Moon.

Birds

American Goldfinches feed on the seed heads of coneflowers and bee balm plants. This is a good time of year to look for Green Herons and Black-Crowned Night Herons along the edges of waterways. And Pelicans are moving through, migrating south. When they are in flight you can recognize them by their white bodies and the black on the leading edges of their wings and on what are called their “primary” feathers, which are the ones at the ends of their wings. The pigment melanin in the black feathers makes those feathers stronger and more resistant to abrasion. White Pelicans have the second biggest wingspan of any bird in North America, behind the California Condor. The Pelicans passing through our area will probably spend the winter along the coast of the Gulf of Mexico.

Mammals

Deer are completing the transition to their winter gray coats, as you can see on the individual in the first and second photos. Deer, like cows, are ruminants. After they eat they regurgitate their food and chew it again to make it easier to digest. The deer in the first photo is probably ruminating. While the antlers of male deer are growing they are covered with a fuzzy substance called “velvet” that helps transport blood into the antlers, which are organs. After the antlers finish growing the bucks rub the velvet off of them and the antlers harden. By this time of year buck deer have grown antlers and rubbed the velvet off of them, leaving bloody scrapes on trees. Antler growth in deer and related species is one of the few examples of organ regeneration among mammals.

Amphibians and reptiles

You may still see frogs and toads out and about, but they are not the only amphibians at Afton. On cool fall mornings after it rains, watch for tiger salamanders moving south of the park to spend the winter in abandoned tunnels and burrows below the frostline. If you see them on 70th street, try not to run them over! That’s where this photo was taken.

Insects

Look for Monarch butterflies passing through, going south. The Monarchs that emerged from their chrysalises in August were in “reproductive diapause”, which means that they weren’t fully developed and won’t be able to mate and lay eggs until next spring when they are on their way north from their overwintering sites in Mexico. This adaptation allows them to conserve energy for their long journey south. How did they know to emerge in reproductive diapause? Scientists think that the developing butterfly inside the pupa is aware of both the length of day, and the age of the milkweed plant to which the pupa is attached, and that these two things signal it to stay in diapause. The butterflies that emerge in August will travel thousands of miles to Mexico and spend the winter in large colonies clustered on Oyamel fir trees. After they leave Mexico to head north these individuals will develop the ability to mate and lay eggs, and it will be their grandchildren or great-grandchildren who will arrive back in Minnesota next spring.

Some of the dragonflies still on the wing in late September are the Lake Darner, and the Twelve-spotted Skimmer. The Twelve-spotted Skimmer takes its name from the number of black spots on its wings. The males also have white spots, while the females do not.

Fungi

We are nearing the end of the season for Giant Puffballs. As you might guess, the Giant Puffball is big, with reports of individuals up to five feet long and over 50 pounds! They are more commonly the size of a softball or maybe a soccer ball. When they are young they have a creamy white exterior and interior. The Giant Puffball doesn’t have a stem, but is attached to its underground mycelium by what’s called a mycelial cord. As they get older, the surface cracks into plates that drop away, exposing millions of yellow to olive-brown spores. Whenever anything touches the Puffball, the spores puff out in a tiny cloud to be carried by the wind, and that’s how they got the name “puffball”. Giant Puffballs prefer rich soil, and you may see them in meadows or along the edges of streams.

Trees

Acorns are falling from oak trees. Many animals eat them and store them to eat during the long winter. There are at least five kinds of oaks at Afton; how many of their acorns can you find?

Northern Pin Oak acorns take two years to mature, so you may see a lot of them in one year and very few the next. Northern Red Oak acorns have very small caps, almost like berets. The caps of White Oak acorns cover the top third of the acorn. Swamp White Oak acorns have knobby caps that cover half the acorn. Bur oak acorns have caps with hairy edges, and the caps cover almost the entire acorn!

Weather observations

Here are some weather observations for this week from past years.

Friday, September 12	2023: clouds early, some sun in afternoon; 2015: 50s in the morning, with a high near 70°
Saturday, September 13	2021: clouds through the day, temperature in the 70s; 2014: overnight low in the 30s, warming into the 60s
Sunday, September 14	2016: high 40s in the morning, rising into the 60s
Monday, September 15	2023: Rain overnight, ending around 8:00; 2022: Hazy sunshine in the 80s. Record low of 36° in 1964, 2007, and 2011
Tuesday, September 16	2023: high 50s in the morning and foggy; 2021: 60s early, rising into the 80s; 2013: temperature in the 60s with an inch of rain
Wednesday, September 17	2021: morning thunderstorm with many downed trees; 2015: Record rainfall of 2.37”;
Thursday, September 18	2022: clouds till late afternoon, high in the mid-60s; 2016: sunny and high near 80°

Photo/Image credits

All photos copyright Nina Manzi, except:

• Bill Marchel: MN Conservation Volunteer: Buck Deer
• Gary Sater: American Goldfinch, Green Heron, First Whitetail Deer
• John Watson, Trail Camera: Buck deer in velvet