by Lee Pfannmuller
In late winter, while Minnesotans are still stoking fires and shoveling out driveways, nearly 3 million waterfowl are stirring in the salty Gulf Coast waters. Ducks are gathering in groups and feeding on small fish, shrimp, midges, and aquatic plants to fuel their northward journey.
Thousands of shorebirds are arriving in the coastal salt flats of Puerto Rico, the midway point for many as they trek from intertidal marshes, mudflats, and lagoons in Argentina and Brazil to the wet meadows and grassy bogs of the Arctic. Ruby-throated hummingbirds, indigo buntings, and ovenbirds are flitting about shade-grown coffee plantations in Guatemala. All will soon join great waves of millions of birds making their annual migration.
Leaving winter homes as far away as South America or as near as Iowa, they respond to environmental and physiological cues, such as increasing hours of sunlight and internal genetic codes. Some birds will settle here in Minnesota; others will simply pass through to breeding grounds in Canada and the Arctic.
The travel log for many migratory species is remarkable. Cerulean warblers, for example, fly more than 2,500 miles from northern South America to Minnesota.
Major storms and freezing temperatures are just some of the hazards that the birds might encounter during their extraordinary journey.
Scott Weidensaul, author of Living on the Wind, described bird migration as "perhaps the most compelling drama in all of natural history."
Minnesotans have a front-row seat to this spectacular show. Millions of spring migrants follow the Mississippi River corridor as they fly north. Birds also fan out from the corridor to important stopover points in the western prairie potholes and northern large lakes and forests. Beginning on the Mississippi's floodplains in southeastern Minnesota, you can follow three waves of spring migration.
Once the ice goes out, waterfowl begin arriving in Minnesota. Look for diving ducks, such as common mergansers and common goldeneyes as early as late February when the water first opens up on big rivers and deep lakes. Puddle ducks, such as northern pintails and gadwalls, turn up later on river backwaters, small inland lakes, and flooded fields.
Nearly 40 percent of North America's waterfowl migrate through the Mississippi River flyway, and this refuge is a key stopover on their journey. From the river town of Wabasha, 261 miles downriver to Rock Island, Ill., the refuge provides ideal backwater marsh habitat. Look for 28 species of geese, swans, and ducks, including tundra swans, American black ducks, ring-necked ducks, common goldeneyes, lesser scaup, and American wigeon. Any overlook on U.S. Highway 61 provides an opportunity for observation. One of the best sites is Weaver Bottoms, eight miles south of Kellogg. Nearby, check the water impoundments along state Highway 74 in the Whitewater Wildlife Management Area. Venture across the river to Trempealeau National Wildlife Refuge in Wisconsin. Don't forget to make a stop at Lake Pepin to see common mergansers.
This 23,000-acre WMA is a complex of wetlands, old fields, oak woodlands, and conifer lowlands. Wetlands and open water cover nearly two-thirds of the site, making it ideal for waterfowl and other waterbirds. It is one of the best sites in the metro area to see sandhill cranes and American bitterns. The trumpeting bugle of a crane can be heard from nearly a mile away, but you will need to get close to the elusive American bittern to hear its distinctive pump-er-lunk call. An extensive network of trails and roads includes a seven-mile, self-guided auto tour.
On the South Dakota border, in Lac qui Parle County, the Salt Lake WMA features a shallow, alkaline lake, which is often covered with waterfowl in April. Brimming with invertebrates, such as brine shrimp, the lake's abundant food resources attract a diversity of waterfowl feeding in the shallow waters and shorebirds feeding in the exposed mudflats. Eared grebes, greater white-fronted geese, avocets, and willets attract birders to the site. Near the lake, a deck with a ramp and benches makes a fine observation spot. A little farther north, near Ortonville, the Big Stone National Wildlife Refuge is another good area to visit. Any wetland or flooded field in western Minnesota can provide food and a resting area for a surprising diversity of ducks, so spend some time exploring the back roads.
As a group, shorebirds log thousands of frequent flyer miles. When white-rumped sandpipers stop to rest in Minnesota, they have traveled nearly 6,000 miles from Argentina and still have a 2,000-mile journey to reach their Arctic breeding grounds. Common shorebirds that nest in Minnesota include American woodcock, Wilson's snipe, and killdeer. A few migratory shorebirds begin to arrive in March, but the majority pass through in late April and May, stopping to rest and refuel before heading farther north into Canada and the Arctic.
An impoundment created by a dam on the Cannon River, the lake is a major stopover for waterfowl and shorebirds. It is relatively shallow when water levels are lowered each spring, so mudflats are exposed on the west end. These mudflats, which shorebirds scour for tasty tidbits, are rich with aquatic insect larvae. Of Minnesota's 41 shorebird species, 31 have been observed here. On a given day, there may be thousands of individual birds. Diminutive least sandpipers and boldly colored American golden plovers are regular visitors. Try to visit before May 15, when managers begin to raise the water levels for summer recreation.
One of the state's newest national wildlife refuges, Hamden Slough features more than 100 restored wetlands, which attract 24 shorebird species during migration, including greater and lesser yellowlegs, solitary sandpipers, Wilson's phalaropes, Wilson's snipes, and marbled godwits. The refuge has an extensive network of roads, making much of the area easy to bird by car. If you are visiting northwestern Minnesota, another excellent site for observing shorebirds is the Agassiz National Wildlife Refuge in Marshall County.
After enduring a drab winter landscape, Minnesotans look for the richly colored palette that songbirds display in their breeding finery. Ready to dazzle the opposite sex, wrens, flycatchers, vireos, and the most sought-after migrants—wood warblers—arrive in peak numbers in mid- to late May. Many of these tiny birds display striking colors with contrasting plumage on the wings, head, and breast. Each sighting is akin to discovering a brilliant jewel flitting among the trees and shrubs. Your adrenaline will soar as you catch a glimpse of the flashy orange throat of a Blackburnian warbler, the bold black necklace of a magnolia warbler, or the dark-chestnut throat and crown of a bay-breasted warbler.
Located in southeastern Goodhue County, along Lake Pepin, Frontenac State Park is renowned for bird abundance. In a single day, birders commonly tally around 120 species, including nearly 20 different warblers. Popular sites include the park trail to Sand Point and the old historic town of Frontenac, located just outside of the park boundaries. Immediately south of the state park and two miles north of Lake City along U.S. Highway 61 is Hok-Si-La Park, which many consider the best place to observe spring warblers.
If you head up the North Shore to catch the migration, make your first stop at Park Point in Duluth. The bridge in Canal Park takes you to one of the longest freshwater sandbars in the world, a natural attractant to migrant birds. The pine forest at the south end is a state scientific and natural area and a great place to bird in May. The site provides welcome shelter during poor weather for waves of migrants heading to the northern forests of Minnesota and Canada. Scan the trees for Cape May warblers, yellow-bellied flycatchers, and Philadelphia vireos. And check the point's sandy beaches and the surrounding waters for terns, gulls, shorebirds, and waterfowl.
Then head farther north, taking the scenic North Shore Drive from Duluth to Two Harbors. Any small wayside is a good site to check, but make sure to stop at the Two Harbors Light Station. At the far end of the parking lot, just below the gift shop, the Sonju Trail circles around Lighthouse Point. The mixed, mature forest provides ideal stopover habitat for songbird migrants, including Nashville, pine, and Blackburnian warblers, as well as white-throated sparrows and Swainson's thrushes.
Itasca State Park attracts about 200 species of birds, including more than 20 warbler species that nest there. Look and listen for pine warblers atop towering old-growth pines, Connecticut warblers in spruce-tamarack bogs, and northern parulas in wet, lowland hardwood forests. Stroll any of the hiking trails with your binoculars in hand.
To get the latest updates on the spring migration, check out the Minnesota Ornithologists' Union hotline. Or call Explore Minnesota at 800-657-3700 (listen to all options and keep choosing the birding reports).