A sharp trill breaks through the white noise of a warm, late spring morning in Horicon and stops Marc Zuelsdorf mid-sentence.
"That's a starling right there," he says, before continuing on about how he's spent a lifetime learning to identify the multitude of species at Horicon Marsh.
Zuelsdorf's father started Horicon Marsh Boat Tours in 1963, and at 11 years old Zuelsdorf led his first on-water tour of the 33,000-acre marsh, one of the country's largest freshwater cattail marshes. The marsh, mostly in Dodge County, is perhaps best known for the annual Canada geese migration that brings hundreds of thousands through the wetland in spring and fall.
But geese aren't the only avian attraction here. And even after decades of leading tours on the marsh, Zuelsdorf still finds himself surprised when he goes out.
"Every tour is different, and I never know what to expect," he said. "Even yet I'm still learning bird songs." He pauses again to point out the call of a blackpoll warbler, a species that migrates through Wisconsin on its way to Canada and Alaska.
More than 300 species of birds have been documented at Horicon Marsh, earning it a designation of an Important Bird Area from the National Audubon Society and a Wetland of International Importance from the United Nations.
The northern two-thirds of the marsh is managed by the U.S. Fish and Wildlife Service as the Horicon National Wildlife Refuge, while the southern third is managed by the Wisconsin Department of Natural Resources as the Horicon Marsh Wildlife Area.
Zuelsdorf credits the two agencies with helping to get the marsh into its current state.
"The marsh now is about the best condition I've seen it in a long time, simply because of the management between the Fish and Wildlife Service and the DNR and the things they're doing to improve habitat," he said. "Water quality is getting better, and the whole marsh improves because of the things they're doing here."
It's been a long road to improvement. In 1846, the Town of Horicon dammed the Rock River, flooding the marsh and creating Horicon Lake, purportedly the largest man-made lake in the world at the time.
Less than 25 years later, the dam was removed and the marshland returned, attracting wildlife and hunters. Unregulated hunting devested bird populations by the early 1900s, when farmers sought to dredge and drain the marsh for moist-soil agriculture. They failed at farming, but succeeded in destroying the wetland.
In 1921, conservationists stepped in and lobbied to restore and protect the area. The state passed the Horicon Marsh Wildlife Refuge Bill in 1927, which led to the building of a dam in Horicon to control the marsh's water levels. In the 1940s, the Fish and Wildlife Service took control of the northern two-thirds of the marsh, and coordinated restoration and management efforts began.
The efforts placed particular emphasis on waterfowl, which is once again abundant here. And one of the best ways to see them is by getting out on the water.
"After so many years of giving tours, there are still a lot of people that come to the marsh and think Highway 49 — all they do is drive around it, never getting out of their car, so never really getting into and seeing it," Zuelsdorf said.
Highway 49 runs east to west through the northern part of the marsh, which is not open to boats. But the state portion, the lower third, is open to motorized and nonmotorized boats, with a number of public launches.
Zuelsdorf leads a variety of pontoon-boat tours including a one-hour sightseeing tour, a two-hour sunset cruise and a two-hour birding adventure.
"In any one- or two-hour tour that we go on, we can see anywhere between 20 and 50 species of birds," Zuelsdorf said.
He also rents canoes and kayaks and offers guided paddling tours. Paddlers can push off from the company's boat landing on the Rock River in Horicon, or be shuttled seven miles north to the Greenhead Boat Landing.
Greenhead is the start of the Horicon Marsh Canoe Trail, a 6.5-mile route that follows the eastern branch of the Rock River through the state wildlife area. Orange and black canoe signs mark the route and correspond with information provided in a brochure from the DNR.
Highlights of the trail include Fourmile and Cotton islands — once home to the largest heron and egret nesting colony in Wisconsin. A severe thunderstorm in 1998 knocked out a large number of trees on the islands during nesting season, destroying nearly all of the nests and causing the birds to flee. Great blue herons have returned, while the egrets have moved and are beginning to form a new nesting colony elsewhere.
The trail follows the river's current, but when water levels are low in summer, Zuelsdorf said, it's negligible anyway. The seven-mile paddle from Greenhead back to Blue Heron Landing in Horicon can take anywhere from 21/2 to four hours.
More ways to see the marsh: Aside from a designated three-mile auto tour through the marsh off Highway 49, visitors can also drive through the the national wildlife refuge portion via the gravel Main Dike Road, half of which is open to vehicles year-round, or a 36-mile route that circles the marsh. Find a map of the routes at fws.gov/refuge/Horicon.
Bike Old Marsh Road, open seasonally from June through August to protect migrating birds. A 36-mile bike route also circles the marsh, with a stretch along the Wild Goose State Trail.
A series of hiking trails around the southern portion of the marsh provides access to a lookout point that's great for birdwatching and taking photos. Access the trails off Palmatory St. just north of Horicon, or near the DNR Education and Visitor Center off Highway 28.
There are also hiking trails and a floating boardwalk in the federal portion of the marsh, intertwined with the auto route off Highway 49.
When to go: Spring and fall are ideal for catching migrations, particularly the geese, but "there's activity going on all the time, especially now that the egg incubation stages are over," Zuelsdorf said. "Birds are looking to find food to feed their young, so they're going to be more active now through June, July and early August, then it starts to settle down."
Early morning and early evening are the best times of day to birdwatch, he said.
How much it will set you back: Admission to the marsh is free.
Pontoon boat tours range from $12 to $20 for adults, with discounts for children.
Canoes are $20/day for a two-person boat and $27/day for a three-person canoe. Kayaks cost $23/day for a single and $40/day for a tandem. Shuttle service is $20 more.
Getting there: Horicon Marsh Boat Tours is at 311 Mill St., Horicon, about one hour northwest of Milwaukee via Highways 41 and 33. The building and boat launch is tucked along the river at the corner of Mill St. and Highway 33.
More information: For more on the boat tours, call (920) 485-4663 or see horiconmarsh.com.
For more on the DNR portion of the marsh, visit the Horicon Marsh Education and Visitor Center at N7725 Highway 28, Horicon. Note that portions of the center are temporarily closed for the construction of new interactive exhibits. See dnr.wi.gov/topic/lands/WildlifeAreas/horicon or call (920) 387-7860.
For more on the federal wildlife refuge, see fws.gov/refuge/Horicon or call (920) 387-2658.
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