Located in the far northwestern corner of Indiana in Lake County and bordered to the immediate north by Lake Michigan?s shoreline, the State Line/Calumet Region Important Bird Area represents perhaps one of the most significant ornithological phenomena and bird conservation issues in the state. This region is regarded as one of the most important flyways for migratory songbirds in the United States, with the shores and deep waters of Lake Michigan acting as a funnel during the spring and fall, thereby generating intense concentrations of migrants within the small woodlots and other green space remaining in the highly urbanized and industrialized Calumet area. Three sites are particularly noteworthy within this IBA ? the Hammond Lakefront Park and Bird Sanctuary, George Lake, and Wolf Lake/Forsythe Park.
The Hammond Bird Sanctuary is located directly on the Lake Michigan shoreline, just east of the Indiana-Illinois state line. Formerly a dumping ground for slag and industrial debris, the developing vegetation at the 9.25-acre sanctuary provides what has become the region?s best documented and most significant migratory songbird resting and feeding location. George Lake, located about 1.5 miles inland from the sanctuary, is an approximate 270-acre complex of open water, herbaceous marshes, and small woodlots that serve as an important oasis for migrant waterbirds, shorebirds, and landbirds. Wolf Lake (plus Forsythe Park), located directly west of George Lake, is an approximate 910-acre site bisected by the state line, of which 385 acres fall within the Indiana border. Both Wolf and George Lake are remnants of a much larger lake that encompassed biologically diverse wetlands, open water, and dune and swale ecosystems; this complex was further connected with Lake Calumet in Illinois and the wetlands of the Grand Calumet River, which have additionally been recognized as an Important Bird Area.
Given the pervasive urbanization and industrialization along this section of Lake Michigan, the sites encompassed by the State Line/Calumet Important Bird Area are acknowledged by birders and ornithologists alike as some of the most imperative for resting and feeding migratory birds. This IBA is situated along the eastern edge of the Mississippi Flyway and is part of the Great Lakes migratory corridor; these spatial considerations, along with the barrier created by the open waters of Lake Michigan, act as a funnel for migratory birds, forcing avian species to converge in great densities in the small patches of habitat remaining in the Calumet Region.
Such high concentrations are especially noticeable for migrant songbirds. In spring during nocturnal flights, north-bound birds may over-fly the shoreline and reverse their course during the morning hours when landfall becomes visible, seeking immediate refuge within the first available green space at the southern edge of the lake. In the fall, the elongated north-south boundary of Lake Michigan helps direct migratory birds toward their wintering grounds; the open waters force avian species to converge at the foot of the lake, near the Calumet Region. When cold fronts and storms approach, the weather magnifies the effects of these spatial features, and ?fall outs? will occur along such lakefront sites as the Hammond Bird Sanctuary, the George Lake Woodlots and Forsythe Park. At such times of intense congregations, the imperative relationship to the habitat encompassed by the Calumet IBA sites and the survivorship of migratory birds is profoundly illustrated.
A partial tabulation WatchList and state-endangered species for landbirds that have been found in this IBA during spring and fall migration include Willow Flycatcher, Marsh Wren, Golden-winged Warbler, Cerulean Warbler, and Nelson?s Sharp-tailed Sparrow. Endangered waterbird species, such as American Bittern and King Rail, as well as declining shorebirds, also frequent the wetlands found within the George Lake and Wolf Lake sites.
The Calumet Region has a long history of environmental problems created by large-scale industrial expansion and residential growth. Surrounding the specific locales listed as part of this IBA are industries such as oil refineries, steel manufacturing facilities, and a coal-fired generating station. This, when combined with the ecological stresses created by one of the highest population densities in Indiana, generates a tremendous amount of pressure on the resources afforded to birds within this significant migratory corridor. Habitat degradation, chemical pollution, and avian disease are just a few of the threats which are pervasive at this Important Bird Area.
The Hammond Bird Sanctuary has perhaps become one of the most captivating examples of bird conservation in the region. Local advocates have worked tirelessly to ensure protection of the sanctuary through the administering of a state-owned conservation easement and facilitating public awareness of the site?s significance to neotropical migrants. However, plans for the potential construction of high-price condominiums to the immediate south of the property as well as continued pressure of use from the adjacent marina have put the value of the lakefront sanctuary at a premium to developers. An expanded trail system and increased recreational usage are just a few examples of proposed changes by city officials which would further marginalize the habitat of this preserve.
George Lake has seen its share of environmental problems, most notably an outbreak of avian botulism that caused a shorebird die-off during the late summer of 2005. This event has helped illustrate the insidious water-quality troubles of the north basin, which offers the best habitat for migratory shorebirds within this IBA. A conservation easement has also been instituted here, and proposed restoration plans and ecological management of the wetland and uplands at the north basin should be undertaken.