This reminds me, during my Loon Watch this morning I was impressed by about 40 Hooded Mergansers on the Inlet to my north opposite the CU & IC crew boathouses, but 150 really is a lot! I thought I heard gunfire far to the north and wondered if the Hooded Mergansers were taking refuge from the lake. In addition to the large number of Hooded Mergansers, I saw a more typical 9 Common Mergansers, and among them two female Red-breasted Mergansers, which is very unusual in Cayuga Inlet. If I had been looking from my windows or deck, instead of from the NYS-89 bridge, they could have been new yard birds. I saw one of them catch a fish.
Also I saw groups of 8, 2, and 20 Double-crested Mergansers in more-or-less southbound flight, which is more than I have seen on the south end of Cayuga Lake recently.