The past few years have been what foresters call “mast years” for oaks and walnuts across northeast Iowa. During prolonged drought, such as the one that has gripped the area since 2020, trees shift energy toward producing large seed crops to ensure the next generation survives if mature trees don’t.
During a recent appearance on the Outdoors in North Iowa program, Butler County Conservation Naturalist Annette Wittrock said that this year, with more favorable weather, acorn production has returned to more typical levels.
“I think we often just forget that trees – like all plants – reproduce by producing and spreading seeds. There are some that do not like this trait about trees, but I do. And so do many animals that live in the woodlands and prairies of our area.”
Wittrock says acorns are power-packed seeds that assist a wide variety of wildlife through the colder months.
“Acorns are high in calories and fat, which help keep the animals warm during the winter months. They also have protein and minerals such as calcium, potassium and phosphorus. All of these combined make them a great source of energy for many animals. Eating a few acorns gives them (those animals) more energy than maybe eating the twigs, bark and leaves that they would have to eat if the acorns weren’t there. White-tailed deer are one of the top acorn consumers. I have read that up to 75 percent of their diet this time of year will be acorns. Other animals that will eat the acorns in our area are woodpeckers, blue jays, ducks, turkeys, and fox to name just a few.”
Wittrock adds that not all acorns are equal though, white oaks offer a sweeter taste with less fat, while black oaks produce higher-fat acorns that are more bitter. Animals often store these acorns for later, forgetting many of their hiding spots, which allows new oaks to sprout—continuing the cycle of life in Iowa’s woodlands.
You can listen to the full interview with Wittrock, along with other guests, on the Outdoors in North Iowa podcast.
