Murphy-Hanrehan Park Reserve is about 18 miles south of downtown Minneapolis in northeastern Scott County.

From the Twin Cities, take I-35W or 35E south to County Road 42 in Burnsville. Go west on County 42 about 2 miles. Turn left (south) on Burnsville Parkway and follow it about 2 miles south and then west (Hanrehan Lake Blvd.) to County Road 75. Turn left (south) on County 75 and go a short distance to the park trailhead building on the east.

Murphy-Hanrehan Park Reserve lies on a steep moraine that was formed during the last Wisconsin glaciation. The topography of the northern and eastern portions of the park is characterized by moderately to steeply rolling wooded hills interspersed with ice-block lakes, ponds, and other wetlands. The steep wooded geologic configuration is a dominant feature of the park and evidence of a significant event in the geologic history of the metropolitan area. The vegetation is mostly closed-canopy, mixed upland hardwoods with a canopy height of 60-80 ft. Oaks (white, northern pin, northern red, and bur oak) are the predominant tree species but there are some smaller tracts of maple-basswood forest and aspen; American elm is also widespread. The forest is not mature, and the oaks generally are younger than 75 years. European buckthorn is the predominant species of the understory shrub layer. Ongoing efforts to control oak wilt disease have created scattered small clearings throughout. A major windstorm in 1998 resulted in more widespread disturbance across the central portion of the forested region. A network of winding trails, consisting mainly of former one-lane dirt roads but also including more recently developed trails, is used by mountain bikers, horseback riders, hikers, birders, and skiers. Although almost no area of the northeast portion of the park is more than 600 ft. from a trail, the woodland seems extensive and remote and the expanding suburbia that abuts to the north and east is barely evident from the interior.

The southern and western portions of the park comprise an open, gently rolling topography with old fields in various stages of succession, restored native prairie, large marshes, small scattered woodlots, plus a few larger woodlots of 50 acres or more. The upland areas were cleared for agriculture prior to acquisition by the Park District. The Credit River and a series of wetlands extend through this portion of the park, draining toward the Minnesota River. The trail system in this part of the park is used primarily by horseback riders.

A variety of habitats allows Murphy-Hanrehan IBA to support an exceptional diversity of over 100 breeding birds. This includes a number of species whose ranges are generally farther north (Yellow-bellied Sapsucker, Chestnut-sided and Mourning Warbler) or farther south (Acadian Flycatcher, Cerulean and Hooded). Twelve species of warblers have bred in this IBA (Blue-winged, Yellow, Chestnut-sided, Cerulean, Mourning, Hooded, Prothonotary, Golden-winged, Kentucky, American Redstart, Ovenbird, and Common Yellowthroat). This IBA supports the only known regular breeding population of Hooded Warblers in Minnesota and other locally unusual breeding species such as Winter Wren, Brown Creeper, and Alder Flycatcher. Common Loons nest annually, possibly the southernmost breeding in Minnesota. Many expected grassland and wetland species also breed in the park, as well as six species of hawks and two species of owls. State-listed species include: Red-shouldered Hawk, Acadian Flycatcher, Cerulean and Hooded Warbler, and Henslow’s Sparrow. This IBA supports substantial breeding populations of Black Tern, Wood Thrush, Dickcissel, and Bobolink.

This IBA is an important migratory stopover site for forest songbirds. Counts in May routinely produce 20-25 species of warblers daily, with peak numbers of several hundred individuals.

Other species characteristic of Upland Deciduous Forest and grasslands include; Broad-winged Hawk, Black-billed Cuckoo, Yellow-billed Cuckoo, Barred Owl, Pileated Woodpecker, Eastern Wood-Pewee, Least Flycatcher, Great Crested Flycatcher, Yellow-throated Vireo, White-breasted Nuthatch, Blue-gray Gnatcatcher, Veery, Wood Thrush, Scarlet Tanager, Eastern Kingbird, Clay-colored Sparrow, Field Sparrow, Vesper Sparrow, Savannah Sparrow, Grasshopper Sparrow, and Eastern Meadowlark.

This IBA offers unprecedented opportunity for long-term avian research and monitoring, and has significance to bird populations within the context of an urban setting.

Urban sprawl is affecting Murphy-Hanrehan IBA—Scott Co., with nearly 55% population increase between 1990 and 2000, is the fastest growing county in the state and development can only be expected to increase. With greatly increased urbanization around the park, there is continually increasing recreation pressure. Current lobbying is for even more trails in the park and for expanded seasons of use. Mountain bike traffic during the current season can be heavy. Expanding the extent of the bike trails and the season to include spring and summer could have deleterious effects on nesting birds. Three Rivers Park District has an 80-20 policy for managing its park reserves: 80% of the park is to be maintained in a natural state, and only 20% will be developed for recreation uses. The current development plan for Murphy-Hanrehan Park includes paved trails, a swimming beach, picnic areas, group camps, and hike-in camp sites. No schedule for development is currently in place.

Oak wilt disease control has been ongoing since at least the 1980s. Heavy machinery is used to cut 4-foot-deep trenches surrounding diseased trees, which are later logged and removed. This has resulted in scattered clearings within the forest, which usually are fairly small. These are in various stages of regeneration. Older clearings appear to have benefited some bird species, including Hooded Warblers which often utilize the increased shrub layer for nest sites. A highly invasive non-native plant, European buckthorn, has become a ubiquitous and dominant shrub throughout the forest, often forming exclusive thickets. It is by far the predominant shrub layer species and native shrubs, including prickly ash and gooseberry, have declined. It also seems to be suppressing natural reproduction of the native tree species.

Predation (and cowbird parasitism) on Hooded Warbler nests is high; predators have not been identified but probably include both mammalian and avian species.