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Grazing
The major historical threat to long-billed
curlews was the removal of primary, native grazers
(i.e., bison [Bison bison], pronghorn [Antilocapra
americana], and prairie dogs), which has altered
the mixed-grass and shortgrass prairies from the
once-heterogeneous, patchy grassland landscape that
resulted from the intense, uneven grazing by these
species. Today cattle and sheep have replaced bison,
but they do not mimic the historical grazing patterns
of these native herbivores.
Because long-billed curlews are found across
such a wide range of climate regimes, from more xeric
in the southern parts of their range to more mesic in the
north, the grassland prairie systems that they occupy
express a similar diversity in plant species composition
and variety, in vegetation height and density, and in
growth form. As a result, one might expect a congruent
variation, from xeric to mesic, in plant species’
response to grazing and in grazing impacts on curlew
habitats. Optimal grazing intensity and appropriate
grazing regimes vary according to prairie type and
climate regimes.
Grazing generally enhances curlew breeding
habitats because it produces the short grass and open
ground that curlews favor for predator detection and
chick mobility (e.g., King 1978, Pampush 1980, Jenni
et al. 1981, Bicak et al. 1982, Cochrane and Anderson
1987, Hooper and Pitt 1996). In the Northern Great
Plains, highest curlew densities occurred in lightly
grazed grasslands on dry soils, and in heavily grazed
areas on moister soils (Kantrud and Kologiski 1982). In
Idaho, curlew numbers were positively correlated with
grazing intensity (Bicak et al. 1982), and breeding was
never observed on rangeland that had not been grazed in
the previous 12 months (Jenni et al. 1981). In Nebraska,
curlews were only observed on grazed areas (Cole and
Sharpe 1976) and only in summer-grazed fields (Bicak
1977). In British Columbia, highest breeding densities
occurred on sites where spring grazing levels averaged
1.4 animal units per ha (Hooper and Pitt 1996). In
habitats with dense stands of perennial bunchgrass,
sheep are better at trampling residual vegetation and
creating appropriate breeding habitat than cattle are
(Jenni et al. 1981, Bicak et al. 1982). In southwestern
Idaho, areas grazed by sheep alone or sheep and cattle
had higher densities of curlews than did areas grazed by
cattle alone (Bicak et al. 1982). A year-round grazing
schedule was least attractive to breeding curlews in
Idaho, and rest-rotation systems that rested pastures
from March through May were also detrimental
(Redmond and Jenni 1982). The best rotation system
included grazing through early spring, so vegetation
height and density were low during courtship and egg
laying (Jenni et al. 1981).
Overgrazing in drier, shortgrass habitats may be
a threat to long-billed curlews and should be avoided
(Strong 1971, Bock et al. 1993, Anstey et al. 1995).
Areas where vegetation is already sparse and short
from overgrazing should be protected to improve their
condition (Oberholser 1974). Grazing in more mesic,
mixed-grass habitats may benefit long-billed curlews
(Kantrud and Kologiski 1982, Messmer 1990). Mixed-
grass areas or areas where the grass is too tall or thick
can be made suitable for breeding long-billed curlews
by implementing moderate grazing (Dechant et al.
2003). Grazing moister areas will increase vegetation
diversity and patchiness and reduce tall, thick vegetation
(Kantrud and Kologiski 1982). In such habitats, some
grazing appears to benefit this species.
Fire and fire suppression
The fragmentation of the mixed-grass and
shortgrass prairies by agricultural conversion has
prevented extensive, uncontrolled wildfires, and those
that do occur are often contained to the smallest area
possible (Bent 1929, Samson and Knopf 1994, Risser
1996). Long-billed curlews may benefit from wildfires
on grassland habitats during late summer (Cannings
1999). Burning can improve habitat for curlews by
removing shrubs and increasing habitat openness
(Pampush and Anthony 1993). Fire suppression may
negatively affect breeding habitat by allowing forest
encroachment and growth of tall grasses and shrubs
(Cannings 1999). During the breeding season following
a fall range fire, there was a 30 percent increase in
estimated curlew breeding density in western Idaho
(Redmond and Jenni 1986). Plant succession following
fire can be rapid, so grazing or mowing must also be
used to maintain burned areas as attractive breeding
habitat for curlews (Jenni et al. 1981).
Exotic species
Early attempts to rehabilitate grasslands included
seeding with exotic crested wheatgrasses imported
from Siberia and planting trees to control wind erosion
(implemented by the Civilian Conservation Corp from
1938 to 1941) (Samson and Knopf 1994). Prairie
restoration efforts that seeded degraded grasslands
with taller, exotic grasses have reduced habitat quality
for grassland nesting birds (Samson and Knopf 1994).
Throughout their range, long-billed curlews prefer native