Ring-billed Gulls show various tail band widths in their first cycle - some thin, others wide. Here's a collection of examples beginning with narrow bands and leading up to wider bands.
|Juvenile Ring-billed Gulls. All photographed on Lake Michigan between July and August.|
I've found that thin tail bands usually taper off and become thinner at the outer tail feathers (see the first bird pictured above), while wide tail bands typically become distally wider (see the last bird pictured above). Here, there is a variable amount of black that creeps up the outer tail feathers and may sometimes reach the bases of these outermost rectrices. This look is much different than that of birds with thinner bands. In short, the amount of variation is appreciable and may cause confusion for those not familiar with it...spread the word!