Spring is usually about verdant trees, singing birds and colorful flowers. For Lake Winnebago however, spring is the time for lake flies to take flight, millions of them at the same time.
As the sun rises higher in the sky in Wisconsin's Lake Winnebago this spring, the quiet morning ambience is usually broken by millions of lake flies buzzing in unison. What begins as a rising crescendo of buzzing soon booms into a full blown fortississimo of noise as swarms of lake flies start to become more active. For locals residing in the area, the yearly hatching of lake fly eggs in Lake Winnebago is nothing new. This year however, experts say that the local lake fly population seems more numerous than usual.
After being delayed by a few weeks, Wisconsin residents and Lake Winnebago authorities have reported that the current population of lake flies is the heaviest it has been in recent years.
"The lake flies have landed," said Wisconsin Department of Natural Resources naturalist Cynthia Mueller. "That means food for incoming bird migrants and Winnebago lake sturgeon is plentiful for another spring season. The spring hatch usually shows up on the east shore of Lake Winnebago on or close to Mother's Day weekend, but this year it is late."
The buzzing swarms of lake flies can be seen in many areas of the lake especially around the shorelines. Previous lake fly hatching seasons usually begin sometime around Mother's Day and can be seen in the eastern part of the lake's shoreline. Sometimes however, strong winds can blow the lake fly populations all the way to the other side of the lake in the western shoreline.
As lake fly activity intensifies when temperatures rise during the mid-mornings in the lake, the swarms can be observed taking flight in complex patters. During windy days, the swarms can appear like little tornadoes moving about the lake's shores. Moreover, the sheer number of lake flies this year means that their buzzing is audible even at relatively long distances.
"Visitors to the park who have never experienced a lake fly hatch are often overwhelmed at what they see," Mueller said. "The sheer number and loud humming is like something out of a Hitchcock movie! A misconception is that these large insects, that resemble mosquitoes, bite."
Unlike mosquitoes, lake flies are harmless to humans. They also serve as a valuable food source for hundreds of other species that live in the lake. A wide variety of birds including thrushes, tree swallows, orioles and purple martins take flight and swoop through the air to feed on the swarming lake flies. While the spring hatching season usually produces larger numbers of these flies, experts say that another hatching period occurs during August. However, the second hatching season is smaller and produces a considerably smaller number of lake flies.
