Normally, the color of the beak in a mute swan does not attain its rich color until approximately 10-11 months of age. Usually, the juvenile swans will have varying ranges of light to dark gray bills. It may be that the color pigmentation showed up prematurely and did not have the full pigmentation to turn the bill its eventual orange color.

Other possibilities could include an illness (due to some internal chemical, hormonal or nutritional imbalance) or possibly a genetic deficit. If this discoloration is a concern, please get the swan to a veterinarian and have them do a physical exam as well as blood work-up. Otherwise, you will need to wait a couple of months to see if the true pigmentation develops. The Regal Swan