Metalized plastic balloons are an environmental hazard for wildlife, since they are not biodegradable and can travel long distances. Today the adult female found one with a Happy New Year's message in Riverside Park and tried to weave it into the nest. The adult male didn't seem to happy with the idea and luckily the balloon fell out of the nest. Stella Hamilton, a long time hawk watcher, retrieved the balloon and made sure it was disposed of properly.
Since these types of balloons are dangerous to wildlife, it's recommended to get children in the habit of popping these balloons at the end of a party as a fun activity, rather then releasing them.