The Minneapolis Chain of Lakes/Theodore Wirth Park IBA includes the five lakes which comprise the Minneapolis' Chain of Lakes; Cedar Lake (173 acres), Lake of the Isles (118 a), Lake Calhoun (422 a), Lake Harriet (343 a) and Brownie Lake, the Thomas Robert?s Bird Sanctuary and Lakeview Cemetery, along with Theodore Wirth Park including the Eloise Butler Wildflower Garden and Bird Sanctuary, the Quaking Bog, Birch Pond, Wirth Lake, the Basset?s Creek pools and the JD Rivers? Children?s Garden. The area is approximately 1-3 miles west and southwest of downtown Minneapolis, most of the land is owned and managed by the Minneapolis Parks and Recreation Board and surrounded primarily by residential neighborhoods.
The northern portion of the IBA consists of several different ecosystems, much of which is forested, although historically a large percentage of this land was covered with oak savannas that have now filled in with native and non-native woody species, turning them into low quality forests with remnant open grown oaks forming part of the canopy layer. The 5-acre Quaking Bog is significant in that it is the only remaining bog of its kind in Minneapolis. A 15-acre tract found in the heart of this area is preserved as the Eloise Butler Wildflower Garden and Bird Sanctuary. Within the Sanctuary woodland, shrub swamp and restored oak savanna habitats are found. Two open water bodies located in the area are Wirth Lake and Birch Pond, there are also numerous active springs, ephemeral pools and streams. The JD Rivers Children?s Garden and 18 hole and Par 3 golf course are located in this area as well.
The southern portion consists of the Chain of Lakes, each of the lakes is surrounded by city park land, most of which is planted with grass and scattered trees and maintained primarily for aesthetics and recreation (walking/jogging, biking, swimming, boating and fishing). Some native vegetation has been planted around the lakes to stabilize shorelines and minimize erosion. Cedar Lake Park, which encompasses 115.08a, contains a natural area of upland deciduous woodland on the northeast side of the lake. A wetland detention pond on the southwest side filters stormwater and snowmelt to enhance water quality in the lake. Lake of the Isles and Lake Calhoun parkland, 90.22 and 96.81 acres respectively, have very little native vegetation except along the shorelines; an exception are the two islands in Lake of the Isles where deciduous woodlands persist. Detention ponds have been constructed on the southwest side of Lake Calhoun and the south side of Isles which function as wetlands to filter water entering the lakes. Kenwood Park (32.94a), which is situated at the north end of Lake of the Isles, contains an upland native prairie located at the north end of the park. Lake Harriet is surrounded by 126.32a of parkland which includes Lyndale Park on the north side of the lake where the Thomas Robert's Bird Sanctuary is located. The sanctuary is a small complex of open water, wetland, bog and native deciduous woods that is a very popular birding spot for city residents, particularly during spring and fall migration. Adjacent to the north boundary of the Robert's Sanctuary is Lakewood Cemetery which provides an open savanna-like habitat for birds. The cemetery may also act as an avian corridor between Lake Calhoun and Lake Harriet. The combined acreage of the parks around the lakes is 461.37. Three of the lakes, Cedar, Isles and Calhoun, are connected by lagoons. A pipeline and channel connect Lake Calhoun with Lake Harriet. The combined water acreage of the four lakes is 1056.
Two-lane boulevards surround the parkland around the lakes with the exception of the north side of Cedar Lake where the native woodland is located. A six lane city street, Lake St., runs on the north side of Lake Calhoun.
A total of 263 species of birds have been recorded within the IBA, including 72 species of Conservation Concern. This reflects both its importance as an oasis of bird habitat in the larger urban area as well as its popularity with Metro birders. From 1977-2005, Steve Carlson collected data on species utilizing the four lakes and adjacent lands. His data breaks down the birds seen by location as follows: Cedar Lake: 209 species, Lake of the Isles: 158 species, Lake Calhoun: 190 species, Lake Harriet: 112 species, Robert's Sanctuary: 197 species, Lakewood Cemetery: 173 species
A black-crowned night heron waterbird colony occurred on the south island in Lake of the Isles from 1981 through 1990. Four green heron nests, 7 great egret nests and 146 black-crowned night heron nests, all in green ash trees, were found in 1981. A high count of 170 total nests was made in 1986. During several of those years, yellow-crowned night herons were observed in the area by both Steve Carlson and myself. The colony was abandoned in 1991. Although waterbird colonies have occasionally become active again after abandonment, it is unknown whether this will happen in such a highly developed urban setting.