Grebes rescue and query

We rescued a pair of grebes from the slushy Lake Manitoba ice on Friday.  They were very close to shore but had become trapped when the ice moved back into shore with the north wind the day before. A pair of chest waders and an insect net made the job quick and 'easy' (although my assistant nearly froze his foot when one of his boots leaked icy cold water).  We released them into the marsh where they seemed very happy and relieved to be able to swim and fish again.

It was an excellent photo opportunity and I managed to get a few really good ones including one I have attached of the pair of them.  I need some second opinions though - the bill color and shape on each of them is a little different, one greenish, one orangish and I'm wondering if the front one is a Western Grebe and the one behind, a Clarke's. There doesn't seem to be much difference in the plumage, but Sibley says that "nonbreeding birds of both species are similar in face pattern, and distinguished by bill color". The one behind also is a little discolored along his bottom edge on the side as he was bleeding a little - nothing serious, upon closer inspection it appeared to have scraped itself on some of the ice shards in the lake. Its bill is also 'reddish' from preening its bloody feathers, but I still think that it looks a little different from the other, shapewise and color.
Heidi E. den Haan
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