We conducted a 4-year experiment to assess the impacts of rotational cattle grazing on rodents and raptors in a mesic coastal grassland in northwestern California. Live-trapping indicated that rodent abundance declined by 69% on the grazed area and increased by 14% on the ungrazed area. Raptor use of the grazed area declined by 15% and increased on the ungrazed area by 63%. Measures of giving-up density indicated that rodents perceived a 25% higher predation risk on grazed area than on ungrazed area, but raptor hunting surveys indicated that risk of depredation from raptors was 2.5 times lower in the grazed habitat, suggesting that rodents use indirect vegetative cues to assess risk.
Johnson, Matthew D. and Horn, Christa M.
"Effects of rotational grazing on rodents and raptors in a coastal grassland,"
Western North American Naturalist: Vol. 68
, Article 3.
Available at: http://scholarsarchive.byu.edu/wnan/vol68/iss4/3