What level of gopher control can I reasonably expect with barn owls?
Barn owls will NOT reduce a rodent problem to zero. However they can make a dramatic difference in an area with an extreme rodent problem and keep it under control. In a mature vineyard, gophers can be reduced to a tolerable level without the use of baiting. Variables include population density of rodents, population density of barn owls, amount of available nesting places in your vicinity,and the presence of Great Horned Owls in the vicinity.
