When cold December nights begin to freeze local ponds and lakes, most waterfowl hunters are packing away their guns and digging out the ice augers. But there are a few hardy souls that brave the bitter temperatures in pursuit of goldeneyes. Also known as whistlers or ice ducks, these rugged diving ducks are the often the last migratory birds found on Lake Champlain as fall gives way to winter, and they offer some of the hottest hunting of the year.