Ring-billed Gull
Identification: Adult- A medium sized gray mantled gull with yellow to greenish-yellow legs, note the distinctly black ring toward the tip of the bill, the red orbital ring and the pale iris. With some retention of basic plumage note the finely streaked crown and nape.
The two birds immediately below (photographed the same day) are adult birds but note the variability in leg and bill color. The third photograph below is of an adult basic plumaged bird with a heavily mottled head.