US Fish and Wildlife bands are silver in color. Color markers are sometimes also used to determine the area they came from and the year they were born. You need to have a good project in place and osprey population numbers need to be up before you can apply for this. One of the parents at this site has a color band on its right leg, along with a silver band on the left leg. We were never able to positively identify the color. Sometimes it looked purple, sometimes green.