Yes, there are several species of terns that live in Wisconsin during the spring and summer months. Terns are seabirds that migrate long distances to breed in the northern United States and Canada. The main tern species found in Wisconsin include the Common Tern, Forster’s Tern, Caspian Tern, and Black Tern.
Common Tern
The Common Tern is the most widespread and common tern species found in Wisconsin. These birds arrive in May to nest and raise their young. Common Terns nest in colonies located along rivers, lakes, and wetlands across the state. There are estimated to be around 5,000 to 7,000 breeding pairs in Wisconsin.
Common Terns build nests on the ground near water. Their nests consist of a scrape or depression lined with grasses, reeds, and other vegetation. Female Common Terns lay 2-3 eggs that hatch after about 3 weeks. The chicks are able to fly within 4 weeks but will continue to be fed by the parents for several more weeks until they fully fledge and become independent.
Some key locations in Wisconsin where Common Terns can be found nesting during the summer include the Lower Wisconsin River, Horicon Marsh, Green Bay, and Chequamegon Bay. They forage for small fish in nearby waters and can often be seen diving into the water to catch prey. In late summer, Common Terns gather in large flocks along the Great Lakes shorelines before migrating back to wintering grounds in coastal areas from the Caribbean to South America.
Forster’s Tern
Forster’s Terns also migrate to Wisconsin each spring to nest and raise their young before returning south in early fall. There are estimated to be 500-700 breeding pairs in the state. This tern gets its name from a naturalist named Johann Reinhold Forster.
Forster’s Terns nest in marshy areas near lakes and rivers, often on floating mats of vegetation. Nests consist of a shallow depression lined with plant material. Like other terns, Forster’s Terns lay 2-3 eggs. After hatching, the chicks are able to fly within 3-4 weeks but will be fed by parents for an extended period as they learn to fish and become independent.
Some of the top breeding areas for Forster’s Terns in Wisconsin include the St. Louis River estuary, Green Bay, Horicon Marsh, and the Lower Wisconsin River. They forage for small fish, insects, and amphibians in shallow marshes and rivers. In migration and winter, they are found along the Atlantic and Gulf Coasts of North America as far south as Central America.
Caspian Tern
The Caspian Tern is the largest tern in the world. This large seabird breeds in scattered colonies around lakes Superior and Michigan in Wisconsin. There are estimated to be only 50-70 breeding pairs in the state.
Caspian Terns build nests on sandy or gravely beaches and islands in early summer. The nest consists of a shallow scraped out area lined with shells, debris, or vegetation. Like other terns, Caspian Terns lay just 1-3 eggs. After hatching, the chicks are able to fly at age 5-6 weeks but will continue to be fed by parents until they fully fledge up to 10-11 weeks.
Major breeding sites for Caspian Terns in Wisconsin include small island colonies in the Apostle Islands National Lakeshore and nearshore islands in Lake Superior. Their large size and massive red-orange bills make them easy to identify. Caspian Terns forage widely for large fish, including alewife and smelt, across Lakes Superior and Michigan.
Black Tern
The Black Tern is a small, black-plumaged tern that nests in wetland areas across much of Wisconsin. There are an estimated 1,000-2,000 breeding pairs in the state. Black Terns arrive in Wisconsin in May and depart by late September for wintering grounds in Central and South America.
Black Terns nest over standing water in marshes, lakes, or ponds. Their nests consist of a floating platform of vegetation anchored to emergent plants. Females lay 2-3 eggs. The young fledge in about 3 weeks but will continue to be fed by parents while they develop flying and fishing skills. Good places to see nesting Black Terns in Wisconsin include Horicon Marsh, Crex Meadows Wildlife Area, and the Lower Wisconsin River.
Black Terns have buoyant, graceful flight. They forage for insects, small fish, and amphibians over open waters by gracefully hovering and diving. These small terns roost on muskrat lodges or floating vegetation at night.
Tern Migration
All of Wisconsin’s tern species are migratory. They winter in coastal areas from the southern U.S. to Central and South America after nesting season. In late April and May, terns arrive back in Wisconsin to breed and nest. By late August and September, they gather in large pre-migratory flocks before heading back to winter grounds.
Terns migrate incredible distances each year, up to 15,000 miles round trip in some cases. They migrate by day, traveling in flocks, and making stopovers to rest and feed. Navigation and timing during migration depends on a combination of innate abilities and responses to factors like weather, wind, and temperature.
Conserving migration stopover habitats is crucial for sustaining tern populations. Major threats during migration include lack of food resources, exposure to predators, adverse weather, and habitat loss. Climate change may also negatively impact migration patterns and timing.
Tern Conservation
Most tern species in Wisconsin have faced population declines over the past decades, primarily due to loss of nesting and feeding habitats. Several terns are listed as threatened or endangered in the state. Ongoing conservation efforts aim to protect and restore nesting colonies and migration stopover sites.
Major threats to terns include:
- Habitat loss and degradation – Draining of wetlands and development of shorelines has reduced nesting habitat.
- Predation – Gulls, crows, racoons, and other predators may eat eggs or young.
- Human disturbance – Recreation, boats, erosion, etc. can disrupt nesting sites.
- Contaminants – Pollutants like mercury and PCBs can accumulate and cause harm.
- Extreme weather – Storms, flooding, or drought can destroy nests/young.
Protection and management of breeding and migratory stopover sites is essential for tern conservation. Public education, restricting human access, and long-term monitoring are also important strategies.
Tern Species | Conservation Status in Wisconsin |
---|---|
Common Tern | Protected nongame species |
Forster’s Tern | Protected nongame species |
Caspian Tern | State threatened |
Black Tern | State endangered |
Conclusion
In conclusion, several species of terns migrate each spring to nest and breed in Wisconsin before returning to coastal wintering areas in late summer and fall. Common terns, Forster’s terns, Caspian terns, and Black terns can all be found nesting in certain habitat types across the state. Terns face threats from habitat loss, human disturbance, predation, pollution, and climate change. Ongoing conservation efforts aim to protect essential tern nesting colonies and migration habitats in Wisconsin into the future.