When biologists create a management plan for a particular site, they think on two levels. The landscape perspective considers how a particular habitat site, or "patch," fits into the surrounding landscape. The patch perspective considers the management of habitat within the site itself. The following sections summarize these considerations, and chapter 2 provides further insight.

Landscape-Level Management

No field or piece of land exists in a void, so it is important to consider the bigger picture of how a particular field or patch fits in with the surrounding landscape to provide regional habitat. The animals and plants in and around a site are affected by and interact with the surrounding landscape, and they don't recognize humandesignated boundaries. In any cropland management effort, be sure to evaluate landscape-level considerations.

Regarding patch size, fragmentation is not an issue with cropland as it is with other habitats. The few wildlife species that use cropland for a primary habitat can prosper as well on a few acres as on several hundred. Generally, though, the smaller an agricultural field, the better it is for a spectrum of wildlife, especially if it is interwoven with other beneficial habitat.

Connectivity and adjacent habitats both come into play in improving cropland for wildlife uses. Depending on your management objective, croplands can be used to augment adjacent habitats, or other adjoining habitats can be developed to enhance a crop field. For example, studies have shown that grassy areas being managed for species that need large expanses of grassland provide more suitable habitat if they are adjacent to open cropland instead of forest. Likewise, adding a strip of'woody cover to a crop-field border would benefit edge species. It is important to consider the proximity of a patch to other habitats and how to incorporate more interspersion of different habitats with the cropland.

Patch-Level Management

Once you have evaluated large-scale considerations, you need to determine the management of the site or field itself. Two criteria must be addressed on any crop field: disturbance and plant-species diversity. The field will not provide suitable habitat for wildlife if the minimum standards are not met for one or both of these.

Disturbance

Different from the other habitats discussed in this book, artificial disturbance is actually a regular process on agricultural lands; in fact, it's what defines this habitat type. So while preventing disturbance is not a goal, appropriate applications
of disturbance-primarily timeliness and amount-need to be considered when managing for wildlife. It is important to follow the guidelines for disturbance timing, intervals, and amount in the subsequent section on agricultural land management.

Plant-Species Diversity

Croplands by nature do not contain a very diverse plant community. Increasing plant diversity in croplands will greatly benefit wildlife. This could mean planting companion crops, creating strips of alternate vegetation, or planting different crops in smaller management units. Rotating crops every year or two years will also improve plant-species diversity on a year-to-year basis.

Agricultural-Land Management for Wildlife

The management of agricultural fields is addressed in three sections: croplands, haylands and pasture, and orchards. Minimum criteria for interspersed or adjacent cover, appropriate management of disturbances, and plant-species diversity need to be incorporated in any agricultural field for the site to provide suitable wildlife habitat. Options to provide 'enhanced wildlife value are also discussed.

Cropland Management

Fields that contain harvested grains or specialty crops should meet the following minimum standards: They should contain at least 2.5% (one acre per forty acres of cropland) interspersed or adjacent wetland, woody cover, or grassland that is managed for wildlife as discussed in the chapters on those habitat types. Fields need to retain a minimum of 30% plant residue until the next year's or next season's crop is planted. Rotate crops at least every three years. Although food is usually not the limiting factor in cropland settings, wildlife may be attracted to unharvested crops or food plots.

Wildlife value can be enhanced on croplands by increasing the amount of interspersed or adjacent cover, increasing the amount of residue, rotating row crops with small grains and grasses and legumes, and rotating crops more frequently. In addition, wildlife value increases with the reduction or elimination of pesticides. Always employ crop scouting to determine specific pest threats and the appropriate pesticide use (if any) to target only those pests that will produce significant economic impact.

Other specific activities to improve interspersion and increase residue are discussed in the later section on additional wildlife management.

Hayland and Pasture Management

Fields that contain harvested grasses and legumes or pastures that are intensively grazed should meet the following minimum standards: They should contain at least 2.5% (one acre per forty acres of pasture or hayland) interspersed or adjacent wetland, woody cover, or grassland that is undisturbed or managed for wildlife as discussed in the chapters on those habitat types. For hay fields, the preferred undisturbed cover is grassland.

Avoid mowing during late incubation (June 10 to July 1) if at all possible to avoid nesting hen pheasant losses. Also, a strip of uncut hay fifty feet wide should be left around all hay-field margins. This may be cut after August 1. For small hay fields, you can increase wildlife survivability by walking the field before cutting to flush out nesting birds and even marking nest locations so they can be avoided during cutting.

Intensively grazed pastures (those that do not meet the criteria in "Grassland Protection With Light Grazing" in chapter 3) should be set up on a rotational grazing system, allowing at least a quarter of the pasture to remain ungrazed for one month during the growing season. Stocking numbers and length of grazing period should result in no more than half of the total annual plant production being removed from the pasture, with vegetation heights never falling below six inches for cool-season pastures and eight inches for warm season pastures.

One way of producing a maximum forage crop while improving wildlife benefit is to raise and harvest native warm-season prairie grasses such as switchgrass, eastern gamagrass, and big bluestem. Studies have shown that nutritional values of these grasses are similar to traditional non-native grasses such as smooth brome and orchardgrass. And the same tonnage of hay can be obtained by just one
annual cutting of these grasses as opposed to three or four cuttings of traditional hay like alfalfa, resulting in less disturbance to wildlife. The timing, too, benefits wildlife. The first cutting of prairie hay usually isn't done until early July, reducing disturbance to nesting wildlife. Remember that native warm-season grasses are cut higher (above the growing point).

Native warm-season grass pastures have advantages for both producers and wildlife. Because the native grasses do most of their growing in the warm months of late May through August and grow much taller than traditional cool-season grasses, they create good cover for wildlife during peak nesting season. Livestock can graze a cool-season pasture from spring through late June to early July and then be switched to the warm-season pasture. Remember that cool-season grasses have a "summer slump" in nutrition.

Assuming that the native warm-season prairie grasses haven't been burned, wildlife can nest and often fledge before livestock are allowed on the native warm-season pasture. And once the livestock are present, the tall grass gives the remaining active nests a better chance to survive. The rested cool-season pasture can then provide brood habitat for late or second-try nesters. Producers benefit because the use of forages at their peak production allows more livestock to graze a smaller area while still receiving adequate nutritional value. Studies show that rotational grazing using both cool- and warm-season grasses produces higher annual weight gain per acre than cool-season pasture alone, thus reducing the costs of production.

See chapter 3 for more information on establishing native warm-season grasses. Seeding rates given in Table 3.3 are for wildlife plantings. Forage plantings require a higher rate. Additional specific activities to improve interspersion of other habitat in pastures and haylands are discussed in the upcoming management section.

Orchard Management

Fields that contain woody fruit crops should meet the following minimum standards: They should contain at least 2.5% (one acre per forty acres of orchard) interspersed or adjacent wetland, woody cover, or grassland that. is undisturbed or managed for wildlife as discussed in the chapters on those habitat types. The vegetation between trees or shrubs should remain unmowed after fruit harvest to provide winter cover. Pesticide use should be kept at a minimum. Crop scouting should be done to determine any problem pests, and pesticides should be used only on those pests that will have economic impact.

Wildlife value in orchards can be enhanced by leaving vegetation between tree or shrub rows undisturbed during the nesting season (April 1 through August 1). Consider using companion plantings between rows to repel or deter known invertebrate pests and thus provide cover and reduce pesticide use.

Additional Wildlife Management on Agricultural Land

Various activities can create additional wildlife cover on farmland. Many have the added benefit of protecting wildlife habitat away from the agricultural site, primarily by reducing or eliminating soil and pesticide movement into aquatic habitats. However, many of these practices, if not managed properly, could function to protect off-site habitat but not provide any habitat on the agricultural field itself For instance, a legume-grass buffer strip forty feet wide can protect a nearby wetland from sedimentation and pollution, but if it is mowed several times during the nesting season, it would provide little benefit to wildlife living near the buffer strip.

The following discussion mentions offsite benefits, but it also focuses on how to manage the land for on-site wildlife benefit. Contour strip cropping, terraces, grassed waterways, and tillage and residue management apply primarily to row-crop, smallgrain and specialty-crop fields, though they can be used on other agricultural lands. Field borders, filter strips, food plots, and miscellaneous applications apply not only to cropland but also to pastures, haylands, and orchards.

Contour Buffer Strips Terraces

Contour buffer strips and terraces can be used on sloping cropland to decrease or eliminate soil erosion. The tops of unfarmable terraces and the alternate strips between row-cropped strips are planted to some type of permanent herbaceous vegetation, usually grasses or legume-grass mixtures. The size of the strip, what is planted, and how it is managed determine its value to wildlife. Strips should be at least ten feet wide,but wider is better. Strip width and number depend on slope and must be compatible with machinery width.

Types of grasses that can be planted are discussed in chapter 3. Terraces are seldom mowed and are good sites for establishing native warm-season grasses and forbs. To provide adequate wildlife habitat, the strips should not be mowed during the nesting season (April 1 to August 1). Also, vegetation should be left unmowed after September 15 to provide winter cover. Terraces and contour buffer strips should be designed by an NRCS soil conservation professional.

Jerry Heinz #####################

From his years growing up on a farm, Jerry Heinz remembers livestock, a variety of grain and legume fields, fencerows, and lots of wildlife. He always "just assumed" the wildlife would be there, but over the years he witnessed the disappearance of small fields, fencerows, and, inevitably, wildlife. Jerry still lives on the Champaign County farm where he grew up in east-central Illinois, and fifteen years ago he decided there had to be a better way to farm. Today he has 900 acres in crop production and 50 acres in conservation programs. He also has a small er farm operation in far southern Illinois (Union County) with about 95 acres in the Conservation Reserve Program (CRP) and 180 acres in the Wetlands Reserve Program.

Jerry signed up for his first CRP acres in 1989. He planted 6-1/2 acres in a switchgrass filter strip, and by 1990 he had his first Acres for Wildlife sign, something he still treasures. Currently he has enrolled all the ground that is eligible in the CRP. He has filter strips, a shallow water wetland, waterways, windbreaks, shelterbelts, and trees. He also has annual food plot acreage, which he plants on his own because it is not part of any program.

Jerry's philosophy has been simple: "It's a good thing to do. The owner knows the land the best and needs to go with what's right. You know what you want and you should go with that." He advises landowners to "use the different agencies and learn how to use the programs. That way you can do what is best for your farm."

While Jerry has seen an economic benefit from the CRP, more important to him is the conviction that he has brought back both the quality and diversity of wildlife. He has seen an explosion of wildlife on his land. Pheasant sightings have gone from a few birds to as many as fifty in a year. Badgers have found a home here, while the groundhogs, which were a problem, have disappeared. Owls are nesting in an old silo, and rabbit and hawk numbers have skyrocketed. One of his favorite sights in the fall is watching Canada geese and mallards drop straight into the corn stubble. "1 wasn't a 'waterfowler' growing up, but I'm hooked now!"

When asked "What do the neighbors think?" Jerry smiles before responding. Some neighbors just shake their heads, but others have stopped to ask questions. On his Union County property, when water control structures were being installed for wetlands, the former landowner wondered "what these kids were up to wasting prime farmland." But this past fall that same skeptic came to watch the ducks.

Perhaps the best indicator of what Heinz's neighbors think is the choice that some have made to duplicate his conservation practices on their own land. As a result, the water quality in the area of his Champaign County farm has improved.

Jerry is modest about his accomplishments. "I can't take credit for how much clearer the water runs or how many more wildlife species call this place home. The credit goes to all the farmers in the watershed who are doing the same, who have made conservation a priority." Yet Jerry Heinz is leading by example - creating habitat where none existed and helping wildlife where he can-and he's doing it the old-fashioned way, one farm and one farmer at a time.

Susan L. Post ###################

Grassed Waterways

The primary purpose for constructing a grassed waterway is to prevent gully erosion by providing a stable, vegetated channel for water to exit a crop field. If shaped and grassed to provide for infrequent mowing, a waterway can also provide some cover for wildlife. Grassed waterways are often less valuable than other grassy cropland applications because periodic inundation prevents ground-nesting species from using the areas successfully. Some species can nest on the upper edges of wide waterways, and certainly many animals can use them for foraging, concealment from predators, and travel lanes.

Fescue and reed canary grass are widely used in waterways, but they are the poorest cover choices for wildlife. Both grasses get extremely thick and are difficult for many species to travel through. Other grass mixtures of species such as brome, redtop, orchardgrass, and the moisture-tolerant native prairie grasses like switchgrass, Indian grass, and big bluestem are much more valuable to wildlife. Follow the guidelines in chapter 3 on seeding recommendations. If a grassed waterway receives repeated traffic from farm machinery, especially early in the growing season, nesting success will be low. Consider mowing such high-traffic areas early, and keep them short to discourage nesting attempts. Cease mowing once the last spray or tillage trip is made. If a grassed waterway does not receive repeated farm traffic, leave it unmowed during the nesting season (April 1 to August 1) and after September 15.

Grassed waterways should be designed by an NRCS soil conservation professional. Cost-sharing may be available. If you plan to leave your waterway unmowed much of the year, make that known before the design is created. Unmowed grass slows water flow more than mowed grass, a factor that will need to be considered.

Field Borders and Filter Strips

Strips of cover along the edges or borders of a crop field can provide significant wildlife habitat while protecting adjacent or nearby watercourses from sedimentation and pollution. At a minimum, field borders and filter strips should be at least ten feet wide; however, for wildlife use, wider is better. The NRCS has standards and specifications for both the widths and vegetation selections for filter strips. Often planting a field border or filter strip requires taking only a small portion of cropland out of production to widen a drainage ditch border, a stream bank, or the perimeter of a field. The wildlife benefits will far outweigh the small reduction in crop acreage. Any of the mixes listed in chapter 3 can be used for field borders and filter strips.

Again, the key to wildlife value is properly managing disturbance to the cover after establishment. Mowing or burning should not be done during the nesting season (April 1 to August 1). Avoid using field borders as travel or access lanes during the nesting season. Leave tall vegetation standing over winter for cover. Burning, mowing, and light discing outside of the nesting season can all be done to prevent woody encroachment.

In some cases, woody vegetation may be desired in a field border or filter strip. It is recommended that a light seeding of grasses and legumes be planted first. Shrubs or trees should then be planted into the herbaceous vegetation. Low-growing native shrubs (such as dogwood, hazelnut, elderberry, American cranberry, and black chokeberry) provide substantial wildlife cover and erosion protection but have minimal moisture and shading impacts on adjacent cropland. If taller deciduous or evergreen trees are desired, tractor-pulled root plows may be used to keep tree roots from extending into the crop field and taking moisture and nutrients from row crops, small grains, or forage crops. Even though field windbreaks may sap moisture and nutrients from adjacent crop rows, they increase total yield over the entire field. These windbreaks reduce wind stress, particularly from dry summer winds.

Chapter 4 provides recommendations for tree and shrub plantings. If you currently have a woody fencerow or field border, consider retaining it and using a root plow to cut any competing roots. This will allow the continued coexistence of valuable wildlife habitat and the farm's commodity crops.

Roadsides

Roadsides that are managed for wildlife provide nesting habitat for pheasants and other grassland birds. Cottontail rabbits and voles increase on these roadsides, and in turn attract red-tailed hawks and American kestrels. While roadsides occupy only 1% of the Illinois countryside, when properly managed, they can provide significant wildlife habitat.

Seeded roadsides provide much better habitat than do unseeded roadsides, which are often mostly bluegrass, broadleaf weeds, and fescue. Roadsides can be tilled and planted with mixtures of smooth brome, alfalfa, red clover, timothy, orchardgrass, redtop, and lespedeza. Native warm-season grasses can be used if special attention is given. Species such as big bluestem and Indian grass are tall and can reduce traffic visibility. Tall vegetation)eft standing over winter may also lead to snow-drifting problems. However, these concerns can be remedied. Native warm-season grasses should not be planted near intersections or farm-lane entrances where traffic safety is a concern. Areas prone to snow drifting can be mowed after the grasses enter dormancy in late fall.

Native cool-season grasses afford some roadside advantages not offered by their warm-season counterparts. Virginia and Canada wild rye are shorter than most warm-season natives and they can be mowed earlier, which addresses visibility and snow-drifting concerns. In addition, they grow earlier in spring than warm-season species, thus providing earlier cover and nesting habitat.

As with all grassy areas managed for wildlife, roadsides should not be mowed until after August 1. Delaying mowing until after the nesting season is the single most important thing farmers and road maintenance personnel can do to benefit grassland wildlife. Delayed mowing not only helps wildlife, it save§ time and fuel. However, if roadside vegetation presents a visibility problem, such as at an intersection, the area should be mowed early and often during the growing season. As well as improving visibility, early and continuous mowing discourages nesting activities that would almost certainly end in failure. Landowners can receive assistance in managing roadsides by contacting district wildlife biologists or the Roadsides for Wildlife program offered by IDNR. Landowners should make every effort to improve roadside habitat because these areas will remain an important habitat component, especially for grassland birds.

Tillage and Residue and Residue Management

Although no-till has become widely used in Illinois, there are still more acres where reduced tillage should be adopted. Just a small change in tillage operations-leaving more residue on a crop field-provides significant wildlife and soil conservation benefits.

Untilled stalks of crops such as corn and sorghum provide some winter cover and help distribute snow evenly over the field. Leaving winter wheat stubble untilled in summer provides brood and roosting habitat for some re-nesting and late-nesting birds. No-till provides even more benefits since soil microorganisms and invertebrates such as earthworms are allowed to increase, providing a food source for many animals. No-till also leaves any post-harvest waste grain on the surface to be used as winter wildlife food. While a minimum of 30% residue must be left on the field at all times for adequate habitat, no-till or reduced-till that leaves larger amounts of residue will provide enhanced value for wildlife.

Another way to control erosion, decrease certain weeds, increase crop-field nutrients, and provide significant habitat for wildlife is to plant companion crops and winter cover crops. Winter cover crops are usually legumes, such as hairy vetch, that grow quickly. In many instances, the spring crop can be no-tilled right into the cover crop. Companion crops are planted between th,e rows of the commodity crop, and their coverage keeps weeds from establishing or flourishing. Both companion and winter-cover crops provide wildlife benefit-primarily increasing foraging and nesting opportunities-by reducing disturbance (tillage and pesticide application) and increasing plant-species diversity.

Food and Cover Plots

Table 6.2  "Food Plot Plant Selection and Management Guide"

Table 6.3  "Food and Cover Plot Seeding Rates and Rotations"

One simple way to provide additional wildlife habitat in a crop field is to leave a portion of the planted crop unharvested through the winter for food and cover. Or you can plant grains and legumes specifically for a fooeJ"and cover plot, providing both valuable shelter from inclement winter weather and an emergency or supplemental winter food source.

Food and cover plots can be planted in a variety of locations with various plant combinations. Here are some basic design tips:

Miscellaneous Applications

Sometimes odd areas are created by an asymmetrical field or machinery turn-around points. These areas represent yet another opportunity to create valuable wildlife habitat. Odd areas can be planted with grass-legume mixtures, shrubs, and trees or as food plots, although food plots may not be needed near grain fields with considerable residue. Manage the area for nesting and wintering wildlife as discussed in the previous sections.

Another simple way to provide some habitat and help reduce pest problems at the same time is to install perch sites in or adjacent to a crop field. Predators of rodents such as hawks and owls use these perches when searching for prey. Aerial insectivores such as swallows need places to rest near their foraging area.

Many of the row-crop areas, especially in central Illinois, have few trees that can be used by these species as perches. Red-tailed hawks often sit on short fenceposts along highways because there are no other perch sites. Adding a couple of perches will provide additional habitat for these species and help reduce rodent and insect pests.

Table 6.2 and Table 6.3 #######

Within the corn-and-soybean farmland of Champaign County exists an oasis - what appears toi be a classic prairie pothole. The hole is ringed with cattail, pickerel weed, and arrowhead. In the shadows, a heron waits silently for a meal. Turtles sun on vegetation hummocks. The area is alive with the calls of birds and frogs.

Plant-Species Diversity

The more plant diversity there is in a wetland system, the more types of wildlife it will support. Different types of wetlands contain vastly different plant communities. Shallow marshes, for example, may have large populations of both submerged and emergent herbaceous vegetation. These plants form different micro-habitats; the underwater plants may provide habitat for aquatic insects and tadpoles while the emergents provide habitat for various bird species. Swamps, on the other hand, are dominated by trees and other woody vegetation, although they also contain their own unique assemblage of herbaceous plants. Every aquatic system, including deepwater lakes and ponds, should have as diverse an aquatic plant community as possible. The more diverse a plant community is, the more likely it is to withstand disease, pollution, water fluctuations, and pressure from wildlife feeding.

If you are reconstructing or restoring a wetland, should you seed or plant wetland plants? Opinions vary, and many factors are involved. Are seeds of desired species on the site in an existing seed bank, or is there a wetland nearby that can serve as a natural seed source? Seeding can also occur from far-distant wetlands almost immediately. Seeds can be carried some distance by water. Waterfowl also will bring in some seeds from distant wetlands on their feathers and feet and in their feces. Perhaps a little patience is in order. Wait a couple of years and see what germinates or moves in naturally. In any event, it's a good idea to get the advice of someone who has had experience in wetland reconstruction or restoration in your locality. If the wetland is smaller than five acres, with no other wetland within half a mile of the site, plan a balanced mix of at least five different species of wetland plants from at least three of the following groups: cattails, grasses, sedges, rushes, bullrushes, and broadleaves. Area coverage by emergent plants may range from a minimum 10% to fully 100% of the wetland.

For individual sites larger than five acres or where there is more than one wetland available for management, a portion of a large individual wetland or one wetland in a complex can be composed of a single species, such as cattails or cordgrass, if the objective is to manage for specific wildlife that use these large single-species stands. Any remaining wetland not in the monoculture should be planned with the minimum standards for wetlands smaller than five acres.

For optimal habitat on any size wetland, at least twenty different species of wetland plants from at least three of the groups just listed should be present. In addition, optimal habitat for wildlife diversity is obtained when area coverage by wetland plants is between 35% and 65%, with the remainder being open water. Following this guideline not only creates a good mosaic of habitat from the mixture of emergents and open water but also ensures some permanent water to allow the establishment of submerged plants.

Successional Stage

While it may not be apparent to the human eye, many wetland systems do age. Lakes and deep ponds advance through successional stages. As sediments and organic matter continue to fill in the bottoms of these aquatic systems, over time they often succeed to shallower habitats. Marshes and other shallow wetlands also go through successional stages. Certain conditions can cause a more rapid change to occur in a wetland. For example, a forested floodplain wetland may experience a severe, prolonged flood that kills many of the mature trees. In just a couple of years this wetland will revert to an early successional stage. Likewise, an upland marsh that experiences prolonged drought may succeed from herbaceous plants to woody cover, and without natural or human-directed disturbances it might eventually become a forested wetland habitat. As humans alter natural hydrologic regimes, some aquatic habitats may advance through succession more rapidly. For example, the natural flushing action of flooding may be reduced, thus allowing sediments to fill a wetland more rapidly and causing faster succession.

Rivers and streams also age in a sense. The older some rivers and streams become and the more sediment and organic matter they accumulate, the more they meander, cutting successively wider channels. A broader channel and floodplain is formed, and new wetlands may be formed when side channels are cut off from the main channel.

Aquatic systems of different successional stages attract different types of wildlife. For example, mudflats and shallow wetlands with annual moist-soil plants, which represent an early successional stage, attract a variety of shorebirds. Many of these same birds are not found in mature wetlands with established emergent vegetation; different wading species would appear instead.

Successional stage can be controlled better in some types of wetlands than in others. Humans have tried to control the succession of rivers and streams by keeping them from changing course, but time has proven that nature often dictates the final outcome. Controlling or retarding succession in other aquatic habitats can be done by a variety of methods, such as reducing the accumulation of sediments and organic matter with proper watershed management. Artificial water-control structures can help manage the successional stage of plant communities in shallow wetlands.

Here are guidelines for providing adequate habitat: One successional stage may be maintained on individual shallow wetlands smaller than five acres. More stages can be provided if desired. Ponds smaller than five acres, however, should have some portion in moist-soil or shallow emergent habitat, in a bay or along a shallow sloping edge. A deepwater pond, without other variation in the terrain, often doesn't provide suitable wetland wildlife habitat.

For wetlands larger than five acres or small wetlands that are part of a larger complex, maintain or create at least two successional stages over the entire wetland area. For example, a portion can be maintained with shallow permanent water with a variety of emergent plants, while the remaining acreage can be used as moist-soil wetland.

Structural Components

Logs, rocks, snags, and physical features such as islands can all be important structural components in aquatic habitats. Many wetlands contain one or more of these components naturally. If not, you should add some.

Most wetlands that have woody cover in or around them contain partially or fully submerged logs and branches. These logs provide cover, feeding sites, and spawning sites for many vertebrate wildlife species, such as frogs, young fish, and turtles. They also provide valuable substrate to which invertebrates can attach themselves. Some wetlands, such as those along creeks and rivers, also contain rocks, which serve a similar purpose to logs.

Snags and den trees can provide valuable nesting sites for wood ducks, prothonotary warblers, and other cavity nesters. Open tree branches can provide perch sites for fish-eating birds like osprey and kingfishers and insect eaters like swallows and flycatchers.

Islands add great diversity to aquatic habitats. Islands can provide safe nesting sites for many wildlife species. They can be especially important in ponds because they vary the terrain and thus diversify the available habitat. A greater variety of structural components in a wetland will attract more types of wildlife. Chapter 7 discusses the use of these structural components in more detail. Minimal standards for creating adequate wildlife habitat include the following: Provide or maintain at least five structural features per acre of aquatic habitat. At least three should be logs in or along the edges of the water, and at least one should be a perch site. For optimum habitat, more components (as many as ten per acre) should be present.