Sweeeet. I got one! I can't take credit for the presumptive ID on the Forster's though. An expert birder was out at the tower calling out birds. Sometimes I was uncertain if I was getting the right bird though.
Thanks so much , Resin. And thanks for the info that #2 was a juvi. He was with the other Black Terns, so I suspected it was the same type of bird even though it was somewhat different.