In our area, we have a few rookeries; communal nesting areas for herons, egrets and cormorants. There are other birds that nest in rookeries but I am not aware of any I our area.
Rookeries are interesting. The two I see most often are in a small cluster of tall trees along side of a river. The birds nest high above the ground. Each bird tends to their own nest. But the colonies can contain two dozen or more nests. The herons, egrets and cormorants will even nest in the same tree. Many believe protection drives their desire to nest communally. More roommates make it easier to spot and chase away predators.
I visited both rookeries last week and it appears to me that the birds are sitting on eggs. If I am right, we should have babies soon. So, I’ll keep checking back and when I can, post pictures. I can’t get close to the nets; I am about 75 yards away. So, I won’t be able to photograph the chicks until they are big enough to pop their heads above the sides of the nest.
Here are a few rookery images. Take note of the male Double-crested Cormorant. He is displaying his orange patch and the crest of feathers on his head. For me, its rare to see the crests displayed.