Not looking good

About a week ago I saw, out my window, a large bird flying toward the rookery, and I thought: oh nice, a heron...then I saw that the large bird had a white tail and I thought: uh oh.

Ever since, I've been seeing fewer and fewer birds on nests at the rookery. For the last two days, I've seen only one bird sitting on a nest.

The leaves eclipse the nests, however. The nests are lare enough that a bird hunkered down in one would not be visible. But there is less activity now, fewer birds to be seen flying around or perched.