so far, over 255 bird species, most of which regularly occur in southern Wisconsin, have been spotted during their annual migrations. Some of the bird species found in the Nature Preserve include the blue jay, American goldfinch, Baltimore oriole, bald eagle, great horned owl, marsh wren, and common loon. However, in recent decades, Lake Mendota has become increasingly eutrophic, and the Wisconsin Department of Natural Resources has documented the presence of numerous invasive species of both plants and animals in the lake. Eutrophication has caused a rapid increase in the abundance of aquatic plants and in the frequency of harmful algal blooms, with the latter being attributable to cyanobacteria. The dominant genera of cyanobacteria in Lake Mendota include Aphanizomenon, Anabaena, and Microcystis, with yearly cyanobacterial blooms occurring in almost every Madison lake since 2017. There are various invasive species in Lake Mendota, including the curly-leaf pondweed, Eurasian water-milfoil, freshwater jellyfish, spiny water flea, water lettuce, and zebra mussel. The spiny water flea in particular has led to devastating ecological consequences in Lake Mendota, as it consumes the native zooplankton Daphnia pulicaria, which has led to marked decreases in water clarity due to increases in the population size of phytoplankton, which are the preferred prey of D. pulicaria. Artifacts On November 2, 2021, a team from the Wisconsin Historical Society raised a dugout canoe to the surface of Lake Mendota. It was discovered by Tamara Thomsen and Mallory Dragt while joyriding on their scooters in June of 2021. At 1200 years old, it is the oldest known sunken boat/shipwreck in Wisconsin. On September 22, 2022, a team from the Wisconsin Historical Society raised a dugout canoe to the surface of Lake Mendota. At 3000 years old, it is the oldest known sunken boat/shipwreck in Wisconsin Gallery See also Lake Kegonsa Lake Monona Lake Waubesa Lake Wingra Lake Mendota Boathouse List of lake monsters Flag of Madison, Wisconsin References External links Information about Lake Mendota's physical characteristics – University of Wisconsin - Madison Limnology Department City of Madison Beaches GAMIS Monitoring Buoy of Lake Mendota Lakes of Dane County, Wisconsin Tourist attractions in Madison, Wisconsin Bodies of water of Madison, Wisconsin