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Landscape and Fine Scale Habitat Associations
of the Loggerhead Shrike
by
Heidi L. Michaels and Jack F. Cully Jr.
Abstract
This study was conducted to determine landscape and fine-scale vegetative variables associated
with breeding Loggerhead Shrikes (Lanius ludovicianus) on Fort Riley Military Reservation, Kansas.
Because Fort Riley is an Army training site, the influences of training disturbance to the vegetation, and range
management practices on bird habitat patterns were also investigated. Breeding birds were surveyed
in 1995 and 1996 using point counts. Survey plots were identified, a priori, at the landscape
scale as either grassland, savannah, or woodland edge according to cover by woody vegetation. In 1996,
fine-scale habitat at survey points and at bird use sites was measured and a principal components analysis used to
characterize the fine-scale herbaceous vegetation structure. A military disturbance index was developed to quantify the severity of
vehicle disturbance to the vegetation at survey and bird use sites. Shrikes were associated with savannah habitat at
the landscape scale. Sites used by Loggerhead Shrikes were characterized at the fine-scale by tall, sparse, structurally
heterogeneous herbaceous vegetation with high standing dead plant cover and low litter cover. At the fine-scale,
tree and shrub density did not differ between sites used and not used by shrikes. Used sites did not differ from
survey sites with respect to military training disturbance, hay harvest, or the number of years since a site was last
burned. Our results in this study suggest that the shifting mosaic of vegetation on Fort Riley resulting from
training and range management practices maintains adequate habitat for breeding shrikes.
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March 13, 2000