Swans?!

I have never seen swans on our lake, until two days ago.  They've been back several times since.  What a treat seeing them!  Of course, I had to look up some information about these beautiful migratory birds.  One of the most interesting facts I learned is that swans mate for life, unless one meets an untimely death, in which case the survivor will generally find another mate. 

I'm finding waterfowl rather romantic these days.  Whenever I see them in the spring, they are usually in a male and female pair.  Sometimes, I get the treat of seeing another male appear and get chased away by the male of the pair, in a "keep your wings away from my gal" kind of a way.  Interestingly, the female often looks bored or disinterested, if there is such a thing among ducks. 

But back to the swans... unfortunately, I'm not sure if these are Trumpeter or Tundra swans.  My picture just wasn't close enough to get a good image of them.  Any thoughts, birders out there?