Managing Habitat for Grassland Birds
A Guide for Wisconsin

Definitions of Grasslands and Grassland Birds

We define Wisconsin grasslands broadly to include all native grasslands, from sedge meadows and open bogs to prairies, savannas, and barrens communities. We also include surrogate prairie grasslands (hereafter "surrogate grasslands"), which represent the vast majority of grassland habitat in the state. Surrogate grasslands are habitats that are similar to and replace the former prairie grasslands chat historically occurred in Wisconsin. Surrogate grasslands include agricultural habitats such as hayfields, small grains (oats, wheat, and barley), row crops (corn, soybeans, and potatoes), fallow fields, old fields, pastures, and set-aside fields. Examples of other surrogate grasslands include young conifer plantations, orchards, parks, golf courses, airports, cut-over or burned-over forests, and mossed bogs (bogs from which sphagnum moss has been removed commercially). Surrogate grasslands also include other idle grasslands, such as those on public lands managed for wildlife. Usually, idle grasslands are composed of non-native grasses and forbs, but they also can be plantings of one or several native species.

Some of the habitats we consider are on the wet (e.g., sedge marshes and open bogs) and woody (e.g., upland shrub and brush prairie barrens) ends of the grassland habitat continuum. They are included because they are used by grassland birds, because they include at least some elements of grassland vegetation structure, and because they represent communities that are not usually covered in management plans for other habitats, such as wetlands or forests.

We consider grassland birds to be those species that use these grassland habitats during the breeding season for courtship, nesting, foraging, rearing young, and roosting or resting. During the breeding season, 105 species regularly or occasionally use Wisconsin grasslands for at least one of these functions, representing 45% of the 233 confirmed breeding species in the state (Robbins 1991; Appendix A). Of these 105 species, 40 require grasslands or a grassland habitat setting for part of their breeding cycle, including nesting or foraging (see sidebar). These 40 species include 17 grassland obligates—species that require grasslands for most or all parts of their breeding cycles and who don't require non-grassland features such as trees. Also included in the list of 40 birds are some species that may not normally be thought of as grassland birds but which occur on either the wet or woody ends of the grassland habitat spectrum, such as shrub-grassland species and birds characteristic of sedge meadows or requiring open water. Sixteen additional species commonly frequent grasslands and may even nest in them but are habitat generalists or are more common in other habitats. These two groups of 40 and 16 species collectively make up the 56 species that are referred to generally in this guidebook as grassland birds. Forty-nine other species occur primarily in other habitats and less regularly in grasslands; these will not be discussed further.

The 40 species that require grasslands during their breeding cycle. Cattle egret Green-winged teal Northern pintail Blue-winged teal Northern shoveler Gadwall American wigeon Northern harrier a Red-tailed hawk American kestrel Gray partridge Ring-necked pheasant Greater prairie-chicken Sharp-tailed grouse Northern bobwhite Yellow rail Upland sandpiper Wilson's phalarope Barn owl Short-eared owl Horned lark Sedge wren Eastern bluebird Loggerhead shrike Bell's vireo Dickcissel Clay-colored sparrow Field sparrow Vesper sparrow Lark sparrow Savannah sparrow Grasshopper sparrow Henslow's sparrow Le Conte's sparrow Sharp-tailed sparrow Bobolink Eastern meadowlark Western meadowlark Brewer's blackbird Brown-headed cowbird a Obligate grassland species are in bold. These are species that require relatively treeless grasslands for most or all parts of their breeding cycles, including nesting and foraging. They may use nongrassland habitats but do not require them for their survival.

The 16 additional, generalist species that commonly occur in grasslands. Mallard Killdeer Mourning dove Common nighthawk Red-headed woodpecker Alder flycatcher Willow flycatcher Eastern kingbird Barn swallow Common yellowthroat Song sparrow Swamp sparrow Red-winged blackbird Common grackle Orchard oriole American goldfinch

The 49 species that occur less commonly in grasslands. American bittern Canada goose American black duck Ring-necked duck Lesser scaup Turkey vulture Merlin Wild turkey King rail Virginia rail Sora Sandhill crane Spotted sandpiper Common snipe American woodcock Ring-billed gull Herring gull Rock dove Great horned owl Ruby-throated hummingbird Downy woodpecker Northern flicker Eastern phoebe Western kingbird Purple martin Tree swallow Northern rough-winged swallow Bank swallow Cliff swallow Blue jay American crow Common raven Black-capped chickadee House wren American robin Gray catbird Brown thrasher Cedar waxwing European starling Yellow warbler Yellow-breasted chat Northern cardinal Indigo bunting Rufous-sided towhee Chipping sparrow Lincoln's sparrow Yellow-headed blackbird Baltimore oriole House sparrow

Grassland Bird Habitat

Grassland bird breeding habitat must fulfill the requirements that a bird has during its nesting cycle. These requirements include suitable habitat structure (which is influenced by management history), adequate habitat size and surrounding land use, sufficient food resources, and sometimes other features including access to open water and nest cavities. High quality habitat fulfills these requirements, attracts relatively high densities of birds, and has high nest productivity. Some habitats that attract high densities of nesting birds may produce few young and therefore are not considered high quality habitat (Van Horne 1983). A more detailed discussion of grassland bird habitat requirements is found in the section, "Guidelines and Recommendations for Habitat Management."

Grassland Bird Communities

Birds with similar habitat requirements (e.g., savannah sparrow and bobolink), or whose requirements differ but are fulfilled in the same habitat type (e.g., savannah sparrow and red-headed woodpecker in open oak savannas), tend to occur together as bird communities. The composition of bird communities varies from site to site, region to region, and year to year because of differences in management history, site conditions, and precipitation patterns and because patterns of bird distribution and abundance vary across the state. As mentioned above, differences in site size, surrounding land use, and woody cover also affect the bird community composition. However, certain bird-habitat associations are fairly constant. Typical bird communities of Wisconsin grassland habitats are presented in Table 1. Some examples follow:

• Horned lark, killdeer, and vesper sparrow are found in plowed and cultivated agricultural habitats, especially early in the season before the crop canopy has developed.

• Vesper, grasshopper, field and clay-colored sparrows, and sometimes lark sparrow occur together in uncultivated habitats with short, sparse vegetation, lots of bare soil, and some shrub cover, such as dry or sand prairies, barrens, and old fields on poor, sandy soils.

• Upland sandpiper, grasshopper sparrow, and western meadowlark may be found together in habitats characterized by short to medium height vegetation, such as moderately grazed pastures, some idle fields of mixed grasses and forbs, open barrens, dry old fields, and sometimes hayfields.

• Savannah sparrow, bobolink, dickcissel, red-winged blackbird, and eastern meadowlark are common associates in relatively mesic habitats with medium vegetation height, such as hayflelds, some idle fields of grasses and forbs, and lightly grazed pastures.

• Sedge wren, common yellowthroat, swamp sparrow, red-winged blackbird, and sometimes Henslow's sparrow are commonly found in habitats characterized by tall, dense vegetation, such as southern sedge meadows and idle fields of grasses and forbs (e.g., switchgrass).

Grassland Bird Distribution and Abundance in Wisconsin

Grassland birds have variable patterns of distribution and abundance in Wisconsin (Table 2). Some species' breeding ranges include the entire state, while others are mainly restricted to certain natural divisions. Even for statewide species, abundance patterns typically vary from one part of the state to another. We record abundance by natural divisions, but it is important to note that species often have highly localized distributions within a natural division. For example, while Brewer's blackbird and clay-colored sparrow are listed as uncommon and rare, respectively, in the Southwestern Upland, they are largely absent from the southern three-quarters of this natural division but are locally common in the north-western part. For further information on ranges, see the sections on natural divisions; see also Robbins (1991), Price et al. (1995), or Temple and Cary (1987).

Management Philosophy

To organize our thinking and approach to grassland bird habitat management in Wisconsin we developed a management philosophy. This philosophy provides the principles that help guide the processes of developing a statewide management plan, determining management priorities, and planning and implementing management actions. The components of this philosophy include emphasizing statewide diversity of grassland birds, promoting management of viable bird populations, managing for bird communities as well as species, creating management plans that are responsive to differences in geographic scales and natural divisions, gauging the effects of management through monitoring, and encouraging public and agency education of grassland conservation issues.

Managing for Statewide Diversity
The overall goal of grassland bird management in Wisconsin should be to maximize statewide diversity of grassland birds rather than just focusing on local diversity. This means providing sufficient habitat for all grassland birds. Managing for local diversity alone tends to promote habitats suitable for the same limited suite or suites of species at the expense of other species and communities with different or unique habitat needs in diverse parts of the state. There are, however, instances when strictly local management is appropriate (such as for the private landowner who wants to increase the number of bird species on his or her property).

The best way to accomplish the goal of statewide diversity is to provide a broad spectrum of habitats and habitat structures in appropriate geographic locations (Ryan 1986). This includes managing for habitats that are not especially diverse either in vegetation structure or bird species richness—for example, tracts of tall grasses and sedges with homogeneous structure, which benefit habitat specialists such as Le Conte's sparrow and yellow rail—or other habitats required by species that are uncommon, locally distributed, or in danger of statewide extirpation.

Diversity across the entire Midwest deserves special attention as well from both planners and managers. The conservation of some species of management concern that occur here may depend less on management in Wisconsin than management elsewhere in their ranges. At the same time, management in Wisconsin is important to species that are relatively common or secure here but are rare or declining elsewhere. Our bird-ranking scheme includes consideration of the Midwest as a whole (see "Identifying Bird Species of Management Concern and Priority Habitats for Wisconsin"). Also, the Partners in Flight program identifies priority species and habitat objectives for the Midwest and other regions (Thompson et al. 1993, Herkert et al. 1996).

Managing for Population Viability
While pursuing the goal of statewide diversity, we should make every effort to maximize the viability of grassland bird populations. Although we lack adequate knowledge of several key issues—including minimum viable population size for nearly all species, habitat characteristics required to maintain a viable population, and habitat or landscape characteristics that enable a population to be a source supplying individuals to other populations that are not maintaining themselves—we must use available data and educated judgment to increase the likelihood that populations are viable. We know that large populations are more likely than small ones to be viable and sustain themselves over time (Herkert et al. 1996). Therefore, managing for large tracts of grassland habitat is the best strategy for supporting viable populations. The larger the habitat block, the more individuals of a given species will likely colonize and establish territories there. Large sites have the advantage of accommodating the needs of species requiring large areas (area-sensitive species) as well as the needs of species that do not. Large tracts of grassland also have a high ratio of interior to edge, thus minimizing the negative edge effects of increased brood parasitism and predation rates, which can reduce nest productivity on small habitat blocks (Johnson and Temple 1990). In addition, large tracts are generally easier to manage than a larger number of small sites. We should not, however, rely on a few large management areas alone, because they may experience local catastrophes or uncontrollable long-term habitat changes. The establishment of multiple large areas, especially within and among different natural divisions, is wise.

Managing for Communities
Statewide management should focus on bird communities as well as on species whenever possible. Community management emphasizes habitats, recognizing that habitats support bird communities, not single species in isolation. Community management is especially important when working with large habitat blocks or landscapes where a large number of species are at risk. However, single-species management can be appropriate when the community management approach will not work for certain species or when specific limiting factors can be identified. For example, single-species management may involve high priority species such as endangered or pest species.

It is almost always appropriate to focus not only on the needs of birds but also on the entire grassland ecosystem, especially including communities of plants, vertebrates, and invertebrates. Management that benefits both grassland birds and other elements of our native grassland biota should receive higher priority than activities that benefit birds alone, except perhaps certain endangered birds. For example, consider two landscapes with potential for grassland management, one of which includes a series of prairie remnants and one with no prairie remnants. The former has the greatest benefits for overall biodiversity (Henderson and Sample 1995).

Scale Issues and Regional Differences
Grassland bird management should be based on a hierarchy of objectives at different levels—statewide, natural divisions, landscapes or areas, and local sites—to achieve the overall goal of maintaining the state's grassland bird diversity. Management should therefore be sensitive to differences among and within the state's natural divisions. Management objectives for each division should be based on:

• Abundance and distribution of priority bird species within the division
• Potential for maintaining, creating, or restoring particular priority habitat types⁶
• Prevalence of competing or complementary land uses and management goals
• Patterns of land ownership

Local management objectives should be based on similar considerations as well as on how local objectives can contribute to achieving natural division and statewide objectives. Objectives vary markedly among local areas. For example, some local areas in the Northern Highland/Lake Superior Lowland have special opportunities for maintaining extensive sedge meadows, which are required by Nelson's sharp-tailed sparrow, yellow rail, and Wilson's phalarope, while some local areas in the Southwestern Upland possess the well-drained, sandy soils needed to provide the barrens habitat suitable for lark sparrows and associated species.

Areas within natural divisions that have relatively low human populations, low land values, or large tracts owned by public or private conservation agencies may be especially appropriate for large-scale projects that benefit species requiring large areas, whereas areas with high human use and high property values may be better managed for other bird species. Some areas with very little potential for grassland bird habitat are best managed for other goals altogether. For example, it is inappropriate to manage for grassland communities in largely forested landscapes or in highly productive row crop land where any habitat created would be isolated. However, large (500 acres⁷ and greater) grassland restorations may be justifiable in some agricultural areas. Statewide management goals can only be attained with the cooperation and coordination of both large landowners (such as the Wisconsin DNR, U.S. Forest Service, USFWS, The Nature Conservancy, northern county forests, and forest products corporations) and smaller landowners (such as southern county forests and other county lands, other corporations, farmers, and other private landowners).

At all scales, grassland bird management should, whenever possible, consider and include private lands to ensure the success of statewide management goals, because there is not enough publicly owned land to do so.

Long-Term Monitoring
Monitoring allows us to assess the response of bird populations to management activities. Long-term monitoring is especially important because surveys that monitor trends over decades lessen the impact of temporary population highs and lows on assessments of trends. Although not commonly practiced, long-term monitoring should ideally include some assessment of reproductive success and habitat conditions, in addition to bird abundance.

There are some long-term monitoring programs already active in Wisconsin, of which the U.S. Department of the Interior's Breeding Bird Survey (BBS), the Wisconsin Checklist Project (Rolley 1994), and several DNR surveys (Robbins et al. 1996) are particularly useful. However, for a variety of reasons, these programs do not adequately monitor the populations of some grassland species (Robbins et al. 1996).

In addition to monitoring within Wisconsin, we need to look at trends elsewhere for species that are at the edge of their ranges in Wisconsin. For these species, long-term monitoring should also consider the status and trends of the population in the center of the range, to help distinguish range shifts and contractions in Wisconsin from overall population changes. Later in this guidebook, we provide more detail on species that are not currently adequately monitored in the state (see Table 3).

Public and Agency Education
Habitat conservation involves partnerships between private landowners, conservation organizations, and public management agencies. Therefore, ongoing public and agency education are essential to fulfill the goals of grassland bird management. Grasslands need to gain equal footing with forest and wetlands in the public's perception of important natural habitats. Because grassland birds are suffering severe population declines, they are a good vehicle for raising public and agency interest in grassland conservation issues as a whole.

Typical sand prairie habitat, showing short vegetation and exposed areas of sand ("sand blows") at Spring Green Preserve in Sauk County. This is one of the preferred habitats of lark sparrows in Wisconsin.

Upland Sandpiper

Eastern Meadowlark

Red-winged blackbird

Ring-necked pheasant

American goldfinch