This news is just sad. Someone in the SF Bay area is catching gulls and putting collars made from beer cans around their necks. Some lager birds are tagged with collars, but these are birds with longer necks like geese and swans. Gulls have short necks and these can collars have sharp edges. Maybe someone is trying to do their own personal study on gulls, but these species are protected and researchers use less traumatic methods to track them like wing tagging, leg banding, or color marking.
(Thanks to A DC Birding Blog for the tip.)