I captured a photo of two Common Loons. In the photo, the top Loon has a black lower bill, while the bottom one does not. Are these in different stages of developing their winter plummage, or is one a juvenile?

http://www.wildmaven.org/birdwatch/loons.jpg

What color are the eyes of a Common Loon? I'm assuming their not red, as these photos show:

http://www.wildmaven.org/birdwatch/looneyes.jpg
http://www.wildmaven.org/birdwatch/looneyes2.jpg