Kinzig and Paige S.Warren of Arizona State University found that the birds of Phoenix prefer the greenery of well-to-do neighborhoods over that in lower-income areas.

• 美国亚利桑那州立大学的金尼格和沃伦发现，凤凰城的鸟类对富裕社区里头绿意的偏好，高于对收入较低的社区里头的。