I wonder if this is where the term "necking" comes from.
Though not as pronounced as the egrets, anhingas have a lore around their eyes in mating season also.
Anhingas have webbed feet, unlike the egret. The male is all black; the female has the brown head and neck.
I do not like the anhingas. They steal the nests that the egrets worked so hard to build and leave the eggs unattended. Then, they destroy them.
Here they are high up in a cypress tree sitting in an egret's nest with the newly laid eggs of the egret.