evidence: One study found that 28 percent of homeless people with previous psychiatric hospitalizations obtained some food from garbage cans and 8 percent used garbage cans as a primary food source. [...] In many cities such as New York, homeless people with severe mental illnesses are now an accepted part of the urban landscape and make up a significant percentage of the homeless who ride subways all night, sleep on sidewalks, or hang out in the parks. These ill individuals drift into the train and bus stations, and even the airports. Many other homeless people hide from the eyes of most citizens. They shuffle quietly through the streets by day, talking to their voices only when they think nobody is looking, and they live in shelters or abandoned buildings at night. Some shelters become known as havens for these ill wanderers and take on the appearance of a hospital psychiatric ward. Others who are psychiatrically ill live in the woods on the outskirts of cities, under bridges, and even in the tunnels that carry subway trains beneath cities.