Afton State Park phenology, April 7 to 13

New nests and much more happening as spring slowly spreads.




4 minute read

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


On Tuesday the 11th the planet Mercury is as bright as it will be all year. Look for it near the western horizon after sunset. Look for the really bright “star”, which is really the planet Venus, then look below Venus for Mercury. And on Wednesday the 12th, find bright Venus and then look to the right to see the Pleiades star cluster. The Japanese call the Pleiades “Subaru” which is why Subaru vehicles have a little cluster of stars on their trim.

Have you ever heard for the Bortle Scale? It’s used to measure the quality of night sky viewing, with measurements ranging from 1 for excellent dark-sky sites, to 9 for inner city skies. The confluence of Trout Brook and the St. Croix River rates a “5”, compared with “9” for St. Anthony Falls on the Mississippi River. Visit to find the Bortle sky for where you live, anywhere in the world!


Juncos continue moving through our area on their way to points farther north. Many of the juncos that we see in April are ones that spent the winter farther south, in Iowa or Missouri. The ones that wintered at Afton are probably already gone. Around mid-April Northern flickers also pass through Afton, like the juncos going north. Flickers are a kind of woodpecker, but unlike most woodpeckers they are ground feeders. They really like to eat ants. They use their beaks to peck holes in the earth, and their long tongues to slurp up ants. Chipping sparrows are returning to our area and will be with us for the summer. Identify them by their red caps.

Mallard ducks, wood ducks and mergansers begin nesting in April, maybe mid-April rather than early April given all the snow we’ve had this winter. When these birds are nesting you are much more likely to see the more colorful male ducks, also called “drakes”, than you are to see the females, called “hens”. Mallards typically nest on the ground, while Wood Ducks and Mergansers are “cavity nesters”, building their nests in hollow trees, old pileated woodpecker holes, or nest boxes, although Mergansers sometimes nest on the ground. Once the eggs are laid the females spend most of the day sitting on their nest and incubating the eggs, and their drab coloring provides excellent camouflage. They leave the nest for only a short time each day to wet and preen their feathers.

Amphibians and Reptiles

On warm overcast or drizzly days you might see Tiger Salamanders leaving their hibernaculae and fanning out across the countryside. There’s a hibernaculum where the salamanders spent the winter somewhere south of 70th St., which leads into Afton, so you could see salamanders in the park! And on warm sunny days look for turtles and snakes basking in the spring sunshine. Turtles may look like they’re just sitting around in the sun, but they’re busy digesting! The warmth of the sun helps them to digest the aquatic plants they ate earlier. If you’re mountain-biking at Afton watch out for basking snakes on the trail so you don’t run one over.


Gray and red squirrels are active all year at Afton. Skunks and raccoons are not true hibernators, but go into torpor to save energy on cold winter days. Now that spring has arrived both skunks and raccoons become more active. If you’re camping at Afton be sure to secure your food for the overnight, or you might wake up to find that a raccoon ate your breakfast!


From now through early fall, each week will see new species of flowers coming into bloom, providing bees and other pollinators with plenty of blossoms to visit. It’s surprising how quickly these flowers appear and bloom once the snow melts. Early bloomers include Hepatica, Bloodroot, Dutchman’s Breeches, Wild Violet, Large-flowered Bellwort, Wild Ginger, and Yellow Trout Lily. Dutchman’s Breeches look like old-fashioned short pants. Wild Violets look like the common garden plant, but the flowers are much smaller and range in color from purple to red.

Bellworts have yellow flowers that hang downward in a cluster, and Wild Ginger has small reddish flowers near the ground that resemble jester’s caps. Trout Lilies take their name from the mottled pattern on their leaves. Consider taking a drive south to Nerstrand Big Woods State Park to look for the Dwarf Trout Lily, which grows in only a few places in Minnesota.

Weather observations

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

Friday, April 72022: rain mixed with snow through day; 2021: thunderstorm in the morning
Saturday, April 82022: dusting of snow overnight; 2021: rain off and on through day, temperature in 60s
Sunday, April 92016: Frost on roofs in the morning, high in the upper 30s
Monday, April 102015: almost an inch of rain over the past week
Tuesday, April 112019: rain and snow through night
Wednesday, April 122022: thunder and lightning in evening; 2020: record snowfall of 6.6 inches
Thursday, April 132021: rain and flurries through day; 2006: record high of 84°

Photo/Image credits:

All photos/images copyright Nina Manzi, except:

  • Keith Henjum: Hooded Mergansers, Raccoon
  • Bill Marchel, MN Conservation Volunteer: Gray Squirrel
  • Alan G. Nelson, Dembinksy Photo Associates, MN Conservation Volunteer: Striped Skunk Dean Lokken: Dark-eyed Junco
  • Gary Sater: Male Mallard Duck, Wood Ducks


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Afton State Park phenology, April 7 to 13