Although for millennia sparrows have been loved by people, and have long lived in the vicinity of people, they have always kept some distance between themselves and people. Regardless, sparrows live almost only where people live. According to a one study, wherever the number of households increases, the sparrows population increases proportionately. Also, sparrows mostly build their nests under the eaves of houses, inside shutter boxes, or in holes in a wall. Although sparrows might nest in holes in tree trunks, this is limited to places such as parks, still close to where people live.
Food is thought to be the main reason sparrows live near humans.
Although sparrows can eat mostly anything, they especially like seeds and grains. Unused land in urban areas is covered with weeds instead of forests, and therefore produces plenty of delicious bird seed, as do the agricultural areas where rice and barley are cultivated. The life pattern of sparrows living and nesting in houses and looking for food near farming areas is thought to stem from this availability of food. However, the recent development of tightly sealed stucco houses has made it difficult for sparrows to nest in houses. As a result, cases of sparrows taking over the nests of swallows and house martins are on the increase.