Hi:
It could be helpful to birders when reporting rare birds to include the age of the bird, particularly with gulls, notable the large, white-headed gulls, also helpful when reporting terns, and very important when reporting Jaegers. These categories of birds arrive sporting a multiple array of confusing plumages so if age is also included with report birders will know more what to look for.
Hope this is helpful
Bob Righter
Denver, CO