Here's a before and after photo - on the left, the normal federal size 2 band, on the right, one shortened for use on a Green Kingfisher. The final height of the Green Kingfisher band is about half that of the normal band. The trimming has to be done to preserve the numbers on the band which are the unique identifier, so excesss has to be trimmed from the top and bottom leaving the numbers legible.
Then file the excess off leaving the band flush with the pliers. Turn the band over, and repeat the process.
A final rounding of the edges of the band on the outside with the file, and smoothing of the inside with a knife, and the band is ready to apply. Total time to make the band: about 2 minutes.