Northern Prairie Wildlife Research Center
Habitat Establishment, Enhancement and Management for Forest and Grassland
Birds in Illinois
Management Guidelines for Grassland Areas
- Avoid fragmentation of existing grassland areas. The preservation and proper
management of existing grassland areas, especially those presently used by
area-sensitive species (Table 2), is the most
effective means of conserving nongame grassland birds. In areas where existing
grasslands are scarce prairie plantings can be very beneficial.
- Grassland restorations aimed at benefiting bird species that are most sensitive
to grassland fragmentation (Table 2) should
be at least 125 acres and preferably more than 250 acres in area. Smaller
plantings less than 50 acres will benefit grassland bird species least sensitive
to habitat fragmentation, but much larger tracts are necessary to benefit
grassland bird species with high sensitivity to habitat fragmentation (Table
- Design grassland plantings for area-sensitive birds to minimize the amount
of linear edge. While circular plots are ideal, square plots are preferred
to rectangular plots of similar acreage. Avoid establishing restorations with
very irregular borders.
- Where 50 acre or greater contiguous restorations are not possible, establish
several smaller scattered restorations. In this design, individual patches
should be at least 15-20 acres in size and preferably be located within a
mile of each other. Guidelines for minimizing edge on these patches should
be followed. It is highly desirable that any adjacent, grassy habitats such
as pastures, hayfields, and grassed waterways be incorporated into the overall
design by using them as connections between grassland patches or as non-woody,
open edges (Figure 6).
Figure 6 - Preferred placement of grassland wildlife areas
in locations where a single, large unit cannot be established. Grassland
wildlife plantings are connected to other grassed areas (for example, the
hayfield) by a grassed waterway, and are sufficiently far from the homestead
and woody hedgerow.
- Locate plantings at least 100 yards from forested areas and activity centers
such as homes and farmsteads. Immediately adjacent land uses should be structurally
open. The planting should not be bordered by tall fencelines or groves of
trees because this woody vegetation attracts nest predators and nest parasites.16
Open pastures, hayfields, small grains, and even row crops are acceptable
- Use mixtures of tall and short grasses for plantings because some characteristic
prairie bird species prefer short vegetation height, whereas others prefer
intermediate to tall vegetation height at the start of the breeding season
(Figure 7). Native warm season grasses are preferred. Recommended tall grasses
for prairie plantings include big bluestem, Indian grass, and switchgrass.
Recommended short grasses include little bluestem, side oats grama and prairie
dropseed. Monotypic stands are not recommended. The use of short grasses will
benefit grassland birds preferring short height grassland areas and may permit
renesting by some species after a nest failure.
Figure 7 - Grassland bird species vegetation height and
density preferences based on studies in Illinois26 and Missouri.54
- Include forbs (native flowering herbaceous plants) in the seed mixture
or supplement with nursery grown stock, if possible. Most grassland bird species
prefer at least low to moderate forb cover (Figure 8). Forbs provide vital
habitat components such as song perches and above-ground nesting substrates
for many species.49
Figure 8 - Grassland bird species forb abundance and low
growing, less than 3 feet, woody stem density preferences based on studies
in Illinois26 and Missouri.54
- Conduct prescribed burns on grasslands managed for breeding bird habitat
in early spring (March to early April) or late fall (October and November).
- Conduct prescribed burns of native or restored prairies over 100 acres
in size in a rotation of 20-30% of the area annually since some species of
grassland birds prefer recently burned areas whereas others prefer unburned
areas.26,50 On small, isolated grassland areas burn compartments
may consist of a larger percentage of the total area, but should not exceed
more than 50-60% in any burn season. In areas where several small plantings
are in close proximity, management should be directed toward providing both
recently burned and unburned habitat by selectively burning parcels on a rotational
- Where possible, use existing 'natural' firebreaks as borders of the restoration.
Roads, lakes, streams, and frequently mowed areas are good examples of firebreaks.
In addition, these edges also may help retard the encroachment of exotic weeds
and woody vegetation on to the grassland.
- Where existing grassland habitats border forested tracts, allow prescribed
fires to burn slowly through the adjacent forest edge into the woods as opposed
to installing a firebreak along the forest edge. This management technique
will create a more natural open or `feathered' edge between the grassland
and forest rather than a sharp, contrasting wall of woody vegetation. Research
indicates that sharply contrasting edges have higher nest predation rates
than `feathered' edges.52
- Remove and control woody vegetation that exceeds the normal grass height.
Several Midwestern studies have shown that grassland birds nesting in proximity
to woody vegetation suffer significantly higher nest predation and nest parasitism
rates than birds nesting far from woody vegetation.16,53
- If hiking trails are to be developed, restrict activities to the edges
of the area. Grassland birds are visible and audible from a long distance
and supplemental plantings can provide adequate viewing of prairie vegetation.
- Grazing, if properly controlled, can be a versatile technique for managing
grassland areas for breeding birds.51,54 Studies in Missouri have
shown that light to moderate grazing may benefit several grassland bird species.54
Light grazing resulting in approximately 40% or more of vegetation cover at
10 inches in height, would benefit grassland bird species with intermediate
vegetation height and density preferences. Moderate grazing resulting in approximately
20 to 40% of vegetation cover at 10 inches in height would benefit grassland
species with low vegetation height and density preferences (see Figure 7).
The most desirable grazing practice would be to keep grazing pressure light
and use a rotation system by which only some sections are grazed and other
areas are left idle. For example, an area could be divided into thirds, with
the three subunits receiving light, moderate and no grazing regimes on an
annual rotational pattern.
- Mow parts of grassland areas for hay or weed or woody vegetation control
as another grassland management alternative. However, such mowing must be
avoided prior to late July or early August because several studies have now
documented high rates of fledgling and nest mortality in grassland areas subjected
to mid-season cutting.46,55,56 Avoid cutting prairie areas very
late in the growing season because this adversely affects plant species composition
and regrowth57, and encourages the invasion of problem grass species
such as Kentucky bluegrass.54 As with burning and grazing, manage
mowed grasslands on a rotational system with some subunits left idle in each
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