Arable land rarely provides a suitable habitat for many species, but crop selection may still be a significant differentiator for species found in farmland areas. A common farmland species like the skylark is widespread on arable fields, but requires a low and dense vegetation such as wheat or barley crops during the breeding season, whereas maize and soy beans do not provide adequate nest cover and grow too tall early in the breeding season. Species of grass grown for hay or seeds may provide a satisfying habitat for several species of birds, but as the grass is harvested rather early during the breeding season of birds, nests and nestlings may be lost during the harvest. The population levels of the skylark is significantly affected by the available food resources which again are governed by the amount of pesticides applied.