Rodent-Prey Content in Long-Term Samples of Barn Owl (Tyto Alba) Pellets from the Northwestern United States Reflects Local Agricultural Change (Report‪)‬

INTRODUCTION Agricultural practices in the United States have evolved remarkably over the past century. Productivity per hectare has, for example, increased tremendously as a result of artificial fertilization and genetic engineering of plant crops. As productivity has increased food surpluses have been generated; simultaneously, soil conservation has become a concern. In the northwestern United States an initial step toward soil conservation was to adopt "no-till" cultivation in the late 1970s where the seed is planted directly through the residue remaining from the previous crop. Alternatively, the residue is burned prior to seeding (Papendick and Miller, 1977; Phillips et al., 1980). Burning was eventually abandoned because of air pollution. In the late 1990s, increasing amounts of previously productive farmland were taken out of production and seeded to grass for a decade or more under contract with the federal government. Such practice eliminates tillage and attendant loss of topsoil from the erosive forces of wind and water, in effect banking top soil for future use, hence the term "soil bank."