Meghan, your photos are excellent. I was at Humber Bay last week and saw these guys but, due to the haze, couldn't get any decent photos. I had never seen the RedHeads before and I'm glad to see your photo of them.
These species are now on Grenadier Pond, just a little east of Humber Bay - all except for the RedHeads! I find the Buffleheads so hard to get pictures of as they dive for a fairly long time and are usually quite far out. Your photos are great!