Rotational grazing decreases the abundance of seed-eating bird species but doesn't affect species with other foraging ecologies

  • Published source details Bock C.E. & Bock J.H. (1999) Response of winter birds to drought and short-duration grazing in southeastern Arizona. Conservation Biology, 13, 1117-1123


This study is summarised as evidence for the following.

Action Category

Exclude grazers from semi-natural habitats

Action Link
Bird Conservation
  1. Exclude grazers from semi-natural habitats

    A site comparison study from December-March in 1996-8 in oak savanna in Arizona, USA (Bock & Bock 1999), found that 19 seed-eating birds were 270% more abundant in a livestock exclosure (former cattle ranch, ungrazed since 1968) than on a ‘holistically managed’ ranch, where 60 paddocks (covering 3,238 ha) were grazed intensively on a short rotation. Twenty-four other species (predators, fruit-eaters and insect-eaters) made up a smaller proportion of total bird abundance and did not differ in abundance between grazed and ungrazed sites. Grasses in the ungrazed area were significantly taller (4.4 times) and had higher basal-area ground cover (2.5 times) and higher overall canopy (2.2 times). The study sites were separated by a 7 km boundary fence, which was divided into 1 km sampling transects.


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