Ring-billed Gulls
(soiled or showing gray wash)
Larus delawarensis

On a regular basis, and mostly during the summer months, Ring-billed Gulls with a grayish wash over their plumage, most noticeably on the normally white parts, show up in the Chicago area. Sometimes this gray coloration is visible on other parts of the bird. My own rough estimate is that close to one in every 100 Ring-billed Gulls along the Chicago beaches in summer shows some amount of this gray wash.

The most likely cause for the gray coloration is that the bird got into some oil, and the oil is discoloring the bird's appearance.

Here are some photographs of one such bird taken by Wouter Faveyts on 29 April 2005 at Chicago's Northerly Island. Wouter is from Belgium and was visiting the Chicago area at the time. With birds like this, shape and structure can be valuable clues to the bird's identity. Compare the gray Ring-billed Gull to its "normal" neighbor.


Here's a more heavily soiled individual, a first year bird, that Tim Wallace photographed on 24 July 2007 at the Waukegan beach (Lake County, Illinois).

This page was last updated on 14 August 2007.
Contact Geoff Williamson with any comments, updates or suggestions.