Landscape and fine scale habitat associations of the loggerhead shrike

This study was conducted to determine landscape and fine-scale vegetative v ariables associated with breeding Loggerhead Shrikes (Lanius ludovicianus) on Fort Riley Military Reservation, Kansas. Because Fort Riley is an Army t raining 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 199 6, fine-scale habitat at survey points and at bird use sites was measured a nd a principal components analysis used to characterize the fine-scale herb aceous vegetation structure. A military disturbance index was developed to quantify the severity of vehicle disturbance to the vegetation at survey an d bird use sites. Shrikes were associated with savannah habitat at the land scape scale. Sites used by Loggerhead Shrikes were characterized at the fin e-scale by tall, sparse, structurally heterogeneous herbaceous vegetation w ith 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 s hrikes. Used sites did not differ from survey sites with respect to militar y training disturbance, hay harvest, or the number of years since a site wa s last burned. Our results in this study suggest that the shifting mosaic o f vegetation on Fort Riley resulting from training and range management pra ctices maintains adequate habitat for breeding shrikes.