Lesser or Greater?

These Scaups have been around the golf course for quite a few years now.  The males are easily recognizable with their white bellies and flanks and by their blue bills.  According to some literature, the Greater Scaups don't actually breed in Alberta so could these be Lesser Scaups?  I think that they are Greater Scaups that are just in the area for a month or two in the spring, on their way to the northern nesting grounds.

Another look at one of the Greater Scaups in the 9th pond.