Important Bird Areas

Murphy-Hanrehan Park Reserve IBA

Minnesota

Murphy-Hanrehan Park Reserve is about 18 miles south of downtown Minneapolis in northeastern Scott County on the Scott and Dakota County line. It lies primarily within the boundary of the City of Savage and in Credit River Township in Scott County. A small portion (about 280 acres) is within the boundary of the City of Burnsville in Dakota County. The City of Lakeville, in Dakota County, is adjacent to the park reserve on the southeast.
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.

Ornithological Summary

Species diversity: With both upland forest and grassland habitat as well as numerous lakes and wetlands, Murphy-Hanrehan Park Reserve supports an exceptional diversity of breeding bird species. A conservative estimate is that 85-90 native species breed annually within the park, and the list of confirmed plus suspected native breeders is over 100. All the expected species in this region of upland forest are represented plus a number of species whose ranges are generally farther north (Yellow-bellied Sapsucker, Chestnut-sided Warbler, Mourning Warbler) or farther south (Acadian Flycatcher, Cerulean Warbler, Hooded Warbler). Nine species of warblers breed regularly in the park ? Blue-winged Warbler, Yellow Warbler, American Redstart, Ovenbird, and Common Yellowthroat are common; Chestnut-sided Warbler, Cerulean Warbler, Mourning Warbler, and Hooded Warbler are less common. Other nesting warblers include Prothonotary Warbler (occasional) and Golden-winged Warbler (formerly). Kentucky Warblers (1-2 territories) have been recorded each of the past 5 summers; nesting is suspected but not yet confirmed.

Some other locally unusual breeding species include Winter Wren, Brown Creeper, and Alder Flycatcher (perhaps the southernmost breeding locality in the state). In 2003 a male Summer Tanager paired with a Scarlet Tanager and the mixed pair fledged a cowbird. Common Loons nest annually, possibly the southernmost breeding area in Minnesota. In 2004 Ospreys nested for the first time. In the mid 1980s, Yellow-crowned Night Herons were regular in summer, apparently from an undiscovered breeding population along the Minnesota River, although there have been no subsequent records. Many of the expected grassland and wetland species also breed in the park, as well as six species of hawks and two species of owls.

With over a square mile of contiguous forest, the park is an important migratory stopover site for forest songbirds, although utilization is difficult to quantify. Field trips in May routinely produce 20-25 species of warblers daily, with peak numbers of several hundred individuals. The park is a consistent locality for Connecticut Warbler in spring migration.

Significant numbers: This site supports the only known regular breeding population of Hooded Warblers in Minnesota. Since the first nesting pair was found in 1984, this species has bred virtually every summer, with up to eight nests discovered per year. In 2003 there were approximately 30 territories and 5 nests were found. It is likely that over 90% of the state?s total breeding population of Hooded Warblers occurs within this park. Acadian Flycatchers have regularly nested here since the 1980s and have increased in number. In 2003 there were 13 territories (possibly representing more than 10% of the state?s population). Also in 2003 there were at least 12 Cerulean Warbler territories, one of the highest concentrations in the state of this globally declining species.

Sites for species of conservation concern: Five State-listed species regularly breed in Murphy-Hanrehan Park Reserve: Red-shouldered Hawk, Acadian Flycatcher, Cerulean Warbler, Hooded Warbler, and Henslow?s Sparrow.

Sites that regularly support significant breeding densities of species of conservation concern in Minnesota: This IBA supports substantial breeding populations of Black Tern, Wood Thrush, Dickcissel, and Bobolink.

Rare, threatened, or unique habitat assemblages: This IBA contains an assemblage of breeding species characteristic of an Upland Deciduous Forest (oak forest) including Red-shouldered Hawk, Broad-winged Hawk, Black-billed Cuckoo, Yellow-billed Cuckoo, Barred Owl, Yellow-bellied Sapsucker, Pileated Woodpecker, Eastern Wood-Pewee, Acadian Flycatcher, Least Flycatcher, Great Crested Flycatcher, Yellow-throated Vireo, White-breasted Nuthatch, Brown Creeper, Blue-gray Gnatcatcher, Veery, Wood Thrush, Blue-winged Warbler, Chestnut-sided Warbler, Cerulean Warbler, American Redstart, Ovenbird, Kentucky Warbler, Mourning Warbler, Hooded Warbler, Scarlet Tanager.

This IBA also contains an assemblage of species characteristic of Native Prairie, including Eastern Kingbird, Clay-colored Sparrow, Field Sparrow, Vesper Sparrow, Savannah Sparrow, Grasshopper Sparrow, Henslow?s Sparrow, Bobolink, and Eastern Meadowlark.

Long-term research, monitoring or urban value: Murphy-Hanrehan Park Reserve comprises about 4 square miles of natural area only 18 miles from downtown Minneapolis, and supports a unique assemblage of bird species. Over 195 species of birds have been recorded in the park by Fall and Carter. As such, the park offers unprecedented opportunity for long-term avian research and monitoring, and has significance to bird populations within the context of an urban setting.

Conservation Issues

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.

Habitat

Murphy-Hanrehan IBA 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.

Land Use

Current recreational development within the park is limited to a network of trails and a trailhead facility for access to the trail system. Nine miles of cross-country ski trails are located in the forested northeastern portion of the park, and over 10 miles of horse trails are located in the south half of the park plus another 2-3 miles in the forested part. 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. 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.