Black-collared Hawk (Busarellus nigricollis) are so named because they have those rather neat black collars (this is one of the more sensible bird names in my view).
These are big, highly visible birds but due to their diet we only ever saw them perched in the tops of the trees lining the various ditches and rivers we toured by boat (as opposed to from the trucks or on foot). Interestingly if you google the species you get a lot of hits from Hato el Cedral so I guess this must be one of the easier places to find and shoot them.
Partly this may be because they'd learned to take baits from the surface of the water here. They are mainly fisheaters (although I suspect they are not above plunging on surface swimming snakes, frogs, mammals etc too) and our guide liked to leave piranha for them to steal from the waters by the boat. I kept missing the moment of truth but got some cool flight shots as they took a look at the bait a couple of times.
Its amazing how the underwing varies depending upon the light.
So there you have it fantastically beautiful with habits that make for easy photography. What more could I want?