Sandhill Cranes in flight

Not sure whether these guys are greater or lesser sandhill cranes. I can tell when they are on the ground where there is some scale, but in the air I have a really hard time. This was taken at Bosque del Apache National Wildlife Refuge. There are thousands of cranes there. Earlier today, we went to the state wildlife refuge at Bernardo. There are 10's of thousands of cranes there. I got to go two days in a row because yesterday I lost my glasses while on a field trip yesterday. Today my son and I went back to look and found the lost glasses in the first 10 minutes! Then we looked at birds there and then went on to Bosque del Apache. This is the crane festival week in Socorro, so I hope to get back more.