Afton State Park phenology, March 31 to April 6

Herons return to their haunts, frogs soon start to sing, and the first flowers are growing.




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Great blue heron, 2019 (Greg Seitz)


Wednesday, April 5th look outside after dark to see the Full Moon. Some of the Native American names for this moon are the Pink Moon and the Egg 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 very early in the spring. And many birds lay eggs in early April, which is the source of the name “Egg Moon”.

And did you know that each full moon happens at a precise time? It’s true! Although the Moon pretty much appears to be fully illuminated for about three days, it’s technically full at the moment when the Earth is exactly in between the Moon and the Sun. In April, that will happen on April 5th at 11:34 p.m. central time. That will be after midnight in the eastern time zone, so the Moon will be full on the east coast on April 6th, but on April 5th here in Minnesota.


Great Blue Herons returned to this area as soon as there was open water. Have you seen any? Other members of the Heron family, including Great Egrets, Green Herons, and Black-crowned Night Herons, are returning, also as waters open up and they are able to hunt for frogs and fish. Look for them along the river and along Trout Brook.

Eagles are one of the first birds to nest, often laying eggs in mid-February. They build big nests of sticks, and use them year after year, each year adding on to make the nest even bigger. You’ll often see the nests in cottonwood trees. Cottonwoods are strong enough to hold the nests, which can weigh up to a ton! Eagle eggs hatch after about a month of incubation. Both parents participate in feeding the hatchlings and protecting the nest. If you are lucky enough to see an eagle’s nest, be respectful and observe it from a distance using binoculars.

Amphibians and Reptiles

Spring peepers and boreal chorus frogs call in the evenings. Wood frogs join the frog chorus in early April. If you are walking through a wooded area with ponds and hear low chuckling that suddenly stops when you get close to it, you’re hearing wood frogs! As you approach the wood frogs can sense the vibrations of your footsteps and think you might be a frog-eating animal, which is why they go silent. If you stand still for a few moments they will resume their chuckling. Peepers and Chorus Frogs are both about one inch long, while Wood Frogs can be much bigger, ranging from one to three inches long.


Hepaticas and Bloodroots may have come into bloom. In the woods and along streams look for Skunk Cabbages. The shoots look rather like the shoots of hostas you might have in your garden. Once you see the leaves of Skunk Cabbages the plants have already bloomed and are forming seeds in a capsule in the center of the plant. During the blooming stage they give off a skunky scent which attracts flies, and the flies pollinate the Skunk Cabbages.


Aspen trees are late blooming this year, but have fuzzy catkins blow down onto the ground in the wind and rain. Aspen trees drop their leaves in the fall, but you may find some on the ground near the trees.

Weather observations

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

Friday, March 312018: One inch of wet snow overnight
Saturday, April 12015: record high of 84°; 2002: record snowfall of 4.6 inches
Sunday, April 22020: pleasant morning, temperature near 40°; 2006: record rainfall of 1.06 inches
Monday, April 32021: lovely day in 70s; 2020: rain and snow off and on throughout day; 2018: record snowfall of 7.5 inches
Tuesday, April 42022: 1⁄2 inch of wet snow overnight; 2021: record high of 85°; 2020: cold overnight, in the 20s in the morning
Wednesday, April 52022: rain off and on through day; 2021: record high of 85°; 2016 red sky in the morning (sailors take warning!) and blustery winds and rain in the afternoon.
Thursday, April 62022: rain changes to snow overnight; 2020: cloudy and mild, in the 50s; 2006: record rainfall of 2.58 inches

Photo/Image credits

All photos/images copyright Nina Manzi, except:

  • Dean Lokken: Great Egret
  • Gary Sater: Bald Eagles, Great Blue Heron, Green Heron
  • Allen Blake Sheldon, MN Conservation Volunteer: Boreal Chorus Frog, Spring Peeper


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Afton State Park phenology, March 31 to April 6