Heron Lake Important Bird Area is located approximately 150 miles southwest of
the Twin Cities, take highway 169 south to Mankato then take MN 60 west through
the town of Wisdom.
IBA encompasses North and South Heron Lake as well as Talcot Lake Wildlife
Management Area with various small lakes and wetlands scattered in between. Ten
other Wildlife Management Areas as well as 4 Waterfowl Production Areas, and 2
County Parks (Sparks Environmental, Talcot Lake) are located within the IBA.
Lake got its name from the vast colonies of nesting black-crowned night herons
that its first visitors found here over a century ago. “Heron Lake” is actually
a complex of prairie lakes and marshes, one of the largest in North America.
This famous chain lies in the heart of the prairie pothole region.
area has undergone many changes in the past century with agricultural
development. The tiling and drainage of lands adjacent to the lake destroyed
much of the vegetation many bird species need for nesting. Although the area
has changed greatly, it is still an important migratory and nesting area for
birds. Cooperative efforts are underway to restore Heron Lake’s teeming bird
life through habitat management and other measures. State Wildlife Management
Areas and county parks around the lakes and wetlands provide not only habitat
but also access for wildlife viewing and other outdoor recreation.
Management Areas (WMAs): The Heron lake IBA contains 11 distinct WMAs which
cover approximately 7,700 acres within this IBA:
Talcot Lake WMA covers 5103 acres and is one of the
largest areas set aside for wildlife in southwest Minnesota. The lake and many
marsh areas in the WMA are formed by a dam on the site's east side and by 2,000
feet of dikes within the WMA. Marshes and upland areas are managed to provide
nesting habitat for many wildlife species, including American Bitterns, Sora
and Virginia Rails, Common Yellowthroats, Indigo Buntings, Bobolinks, Gray
Partridges, Northern Harriers and several species of sparrows.
The Timber Lake WMA is the second largest WMA within the
IBA boundaries and is mostly composed of wetland/grassland habitat with some
Production Areas (WPAs): Heron Lake IBA also contains 3 WPA units in Jackson County:
Spring Lake WPA, Timber Lake WPA and
LaCrosse WPA, and one WPA in Cottonwood County, the Clear Lake WPA. These 4 WPAs collectively cover 1183 acres.
importance of North Heron Lake
to birds has been known since the early 1900s. In June 2007; the Minnesota Biological
Survey (MBS) conducted breeding bird surveys at North Heron Lake as part of a
broader survey of Jackson, Cottonwood, Martin, and Watonwan counties.
familiar with North
know that it is much more than just open water.
A diverse mix of habitats surrounds the lake, including emergent marsh,
shrubby willow thickets, wet grasslands, and scattered patches of trees and
small woodlots. Diverse habitat means high
bird diversity. The final tally for MBS
bird surveys was an impressive 77 bird species.
Almost all of the typical marsh birds were found, including 10 duck
species, nesting Western Grebes, American White Pelican, the secretive Least
Bittern, Virginia Rail, American Coot, Black Tern, Marsh Wren, Swamp Sparrow,
Red-winged and Yellow-headed Blackbirds.
Rarer species found included Trumpeter Swan (a state-threatened
species), American Bittern (relatively rare in southern Minnesota), Forster’s Tern (a state special
concern species). Also observed was the
Great-tailed Grackle, a large cousin of the Common Grackle that has recently
moved into Minnesota
from the south. Great-tailed Grackles
were first documented nesting in Minnesota in
County in May 2000. In our area, this species is a relatively
secretive, marsh-nesting bird.
around North Heron Lake support species such as Red-tailed Hawk, American
Kestrel, Sedge Wren, Clay-colored Sparrow, Savannah Sparrow, Grasshopper Sparrow,
Dickcissel, Bobolink, and Western Meadowlark.
Shrubby thickets are home to species like the Willow Flycatcher, Yellow
Warbler, Common Yellowthroat, and Song Sparrow.
Woodlots and others areas of trees and shrubs provided suitable habitat
for species like Great Horned Owl, Yellow-bellied Sapsucker, Great Crested
Flycatcher, House Wren, Rose-breasted Grosbeak, and Indigo Bunting. The Red-headed Woodpecker and Blue Grosbeak
have also been documented within this IBA.
Heron Lake has become one of the most popular walleye fisheries in
southern Minnesota. With a shallow lake depth and ideal vegetation for this
species, recreational fishing has become popular. With high boat traffic
colonial Waterbirds such as Franklin’s Gulls and Black Terns are fighting human
interaction as well as common natural factors. Over the past years a decrease
in vegetation has been noted. These colonial water nesters often return to the location
from which they fledged. Returning individuals are finding scarce availability
of nesting sites. Factors such as high precipitation levels and large waves
caused by boaters flood the nests of these birds. With fewer gulls and terns
fledged at the colony locations fewer birds are returning to the breeding
grounds. Less vegetation also means less food stores for these birds. High wave
activity can also prevent the establishment of emergent vegetation.
Tilling and drainage of nearby farmlands is also a concern to water
quality and the drainage effects on water level. The Heron Lake system is prone
to extreme water level fluctuation because of the amount of drainage into the
watershed. A heavy rainfall event in the watershed results in very rapid water
level increases which greatly affect the waterbirds nesting in the system.