I had heard these guys (and gals) had appeared last week and was disappointed to have missed them, but they made an appearance today! Sadly the sun and the weird setup of our office and its windows put a ghost of my hand right in the shots I managed to get...
The common mergansers were clustered just off to the left of the hooded ones, like they didn't quite get along.
We spotted a group of mergansers outside our office window yesterday, but none of us knew what they were. Saw them again today and overheard some people (of some bird authority) saying they were common mergansers, and that hooded mergansers had also been seen hanging around last week.
Spotted the guy (or gal?) perched on a low branch of a tree by the Cambridgeside Galleria. It's breast was very white with black speckles and I didn't particularly notice a red tail on it, so it may have been a juvenile? Didn't see it in flight, so can't say for sure.