How does one determine the sex of a gull?

At 09:04 AM 1/31/2005, you wrote:
>Leo, et al.:
>
>Shrimpy shows up whenever she pleases. Sometimes the gull flock arrives at
>the Seabreeze fairly early in the morning. Sometimes Shrimpy arrives solo
>when there are few other gulls around. The trick is to not be there at the
>crack of dawn and not too near late afternoon. Other than that, it's a crap
>shoot!
>
>Please note that Shrimpy is getting old. Since she's at least 11 years old,
>if you haven't seen her yet, time is ticking. Plus, by the end of February,
>she starts to wander and the chance of seeing the gull drops from almost
>100% to about 50%. Later in the warmer months, it drops even more.
>
>This Saturday is the Patuxent River Waterfowl Survey coordinated by Jug Bay
>and Shrimpy has been accounted for each year since its inception. The count
>runs from 7:30 to 10:30. An extra set of eyes to ID Shrimpy during the count
>would be nice.
>
>Tyler Bell
>
>California, MD