Afton State Park phenology, April 19 to 25

View of the St. Croix River from Afton State Park in spring. (Brett Whaley/Flickr)

Astronomy

Look outside after dark to see the Full Moon. Some of the Native American names for this moon are the Pink Moon and the Maple Sap Boiling Moon. The name “Pink Moon” is an Algonquin name from the northeastern part of North America, and refers to a plant called Moss Pink, or Creeping Phlox, which blooms early in the spring. And while maple sap has stopped running in our area, it may still be running farther north where the Ojibwe pioneered the making of maple sugar and maple syrup in springtime sugar camps.

Birds

Many of the migratory birds that will nest at Afton have returned from the south. On the prairie look for Meadowlarks, Eastern Bluebirds, Tree Swallows, and Bobolinks. Meadowlarks wintered in the southern part of the United States, Eastern Bluebirds in the U.S. or Mexico, Tree Swallows in Florida and Central America, and Bobolinks went all the way to South America. Tree Swallows often nest in bluebird boxes. One of the reasons the bluebird boxes at Afton are set out in pairs is that the tree swallows that occupy one box will not tolerate another pair of tree swallows nesting in the second nearby box. But they don’t mind if bluebirds nest there!

Down by the river look for Great Blue Herons along the banks and Loons passing through on their way north. A few loons may spend the summer on lakes in our area, but most go farther north. Along the edges of the woods look for Pheasants and for Pileated Woodpeckers, who may be busy pecking out new nest holes. Woodpeckers make new nest holes every spring, which leaves the old nest holes available for use by other animals. Woodpeckers may choose a place on a dead tree where the bark has been softened by fungi, and may even transport that particular kind of fungus on their beaks from one tree to another.

Amphibians and Reptiles

Look for both Painted and Snapping Turtles basking on sunny days. Both species live at Afton. The warmth of the sun helps them to digest what they’ve eaten.

Insects

There are two species of “lady” butterflies at Afton in the summer – the Painted Lady and the American Lady. It is too cold for the ladies to over-winter in Minnesota, so like the Monarchs they go south for the winter. Also like the Monarchs, it takes several generations to make the return trip north to Minnesota. The Painted Ladies don’t go far south and return sooner than the Monarchs, arriving in late April. We usually don’t see American Ladies until later in the year – they have an established population in the southern United States and successive broods make their way farther and farther north over the course of the summer. The two species are very similar in appearance. If you see them when they’re perched, the American Lady has two big eyespots on its hind wing, while the Painted Lady has four smaller eyespots. The Painted Lady is the most widespread butterfly in the whole world – it lives on all continents except Australia and Antarctica.

Red Admirals are another butterfly that migrates, and like the Painted Lady may return to Afton as early as late April. Red admirals overwinter either as adults or in the pupal stage, when the larva has transformed itself into a chrysalis but not yet metamorphosed into a butterfly. Overwintering Red Admirals do not survive very cold temperatures, so the ones we see here in early spring have probably flown in from farther south. But you never know, especially with the generally mild winter we had. And you might also see Mourning Cloaks and Eastern Commas, which overwinter at Afton as adults and are on the wing as soon as we start having warm sunny days.

Plants…and Fungi

Some of the spring ephemerals still blooming are Large-flowered Bellwort, Yellow Trout Lily, and Wild Violets. Wild Violets have an unusual strategy for dispersing their seeds called “Ballistic Dispersal”. Their seeds form inside a capsule that explodes when the capsule dries and compresses the seeds. The seeds are covered with a sweet substance that is attractive to ants. Ants gather the seeds and take them underground, but just eat the sweet stuff on the outside of the seed, and not the seed itself, in effect planting the seeds in a new location!

And while you’re looking for spring ephemerals in the woods, keep a lookout for the bright red of the scarlet cup fungus. The “cup” is the fruiting body of an organism that is more like animal than a plant, and the organism sends up its fruiting bodies from underground at about the same time the spring ephemerals bloom.

Along the edges of the woods look for Kittentoes and Little-leaf Buttercups, and on the prairie look for Prairie Smoke. Kittentoes are a member of the genus Antennaria, which takes its name from stamens that project out away from the flower like the antennae of insects. The Antennaria are a favorite host plant of the both the Painted Lady and the American Lady butterfly, so if you see a caterpillar on kittentoes it may become a Lady butterfly someday.

Weather observations

Here are some weather observations from the Afton State Park area from past years.

Friday, April 19	2023: Thunderstorm in the evening; 2020: partly sunny with a cold wind, temperature in the 50s; 2013: 6” heavy wet snow overnight
Saturday, April 20	2023: rain throughout the day, temperature in the 40s; 2022: rain the afternoon, temperature in the 40s; 2019: sunny and in the low 70s; 2013: record low of 21°
Sunday, April 21	2022: Sunny day in the 50s; 2016: ¼” rain overnight, in the 50s; 2002: Record snowfall of 6.6”
Monday, April 22	2020: pleasant day in the 60s; 2001: record rainfall of 2.21 inches
Tuesday, April 23	2022: Temperature in the 60s, with thunderstorms in the morning and evening; 2016: clear and temperature in the 40s in the morning, with dew on the grass
Wednesday, April 24	2017: high 40s in the morning, rising to 72°
Thursday, April 25	2022: gray and drizzly, frost in the morning, high temperature in the 30s; 2013: Partly cloudy with a high in the 50s