We returned to the north end of Mackay Reservoir early this evening and found the juvenile Sabine’s Gull again in the same place. It was extremely tolerant or our presence, coming within 10 feet of us multiple times. (With better reflexes and a faster camera, I could have gotten incredible photos when it flew right towards me, veering at the last moment!) After about an hour, a second juvenile Sabine’s Gull showed up in the same area. 
If interested in seeing these, turn west at the northernmost marked access point for Mackay Reservoir off Hwy 93 and go down to the water’s edge. They are feeding in muddy patches right on the shoreline as well as out in the water less than 20 feet off shore.
Wendy McCradyMackay, ID