The bald eagle population in Wisconsin has made a huge comeback in the last 45 years.
According to a new survey released by the Wisconsin Department of Natural Resources, the state has shown a dramatic increase in the total number of active bald eagle nests since 1974.
The aerial nesting survey of 2019 observed 1,684 occupied bald eagle nests in 71 of 72 counties.
Jim Woodford, the section chief of field operations for Wisonsin DNR, told ABC News that the data published in the maps "were collected through annual low-altitude aerial flights completed by Wisconsin DNR pilots and biologists."
"These surveys were completed during the bald eagle’s egg incubation stage to determine nest occupancy and the chick rearing stage to determine nest success," he explained. "The 2019 surveys marked our 47th consecutive year in completing these flights."
"Part of that public support includes donations to the Endangered Resources Fund via Wisconsin state income tax forms, purchases of an Endangered Resources license plate and citizen reports of bald eagle nests or nest-building activity."
The bald eagle nest occupancy survey was flown in March and April to locate occupied nests. Additional ground observations were provided by landowners, birders, volunteers, and raptor banders; this information is used to supplement and check aerial data.