[EDIT]: most likely a pigeon: http://www.birdforum.net/showthread.php?t=85789
Seems not quite adult.
Found stumbling around alone on the ground in an Outback Steakhouse parking lot in Tempe, Arizona, USA. Very warm May weather. Sharp beak, large feet, protruding sternum (for lack of better terminology).
http://i66.photobucket.com/albums/h261/agent6488/b10.jpg
http://i66.photobucket.com/albums/h261/agent6488/b9.jpg
http://i66.photobucket.com/albums/h261/agent6488/b8.jpg
http://i66.photobucket.com/albums/h261/agent6488/b7.jpg
http://i66.photobucket.com/albums/h261/agent6488/b6.jpg
http://i66.photobucket.com/albums/h261/agent6488/b5.jpg
http://i66.photobucket.com/albums/h261/agent6488/b4.jpg
http://i66.photobucket.com/albums/h261/agent6488/b3.jpg
http://i66.photobucket.com/albums/h261/agent6488/b2.jpg
http://i66.photobucket.com/albums/h261/agent6488/b1.jpg