There both important groups, but DU is way to political and tries to keep all the user groups happy and not piss anyone off. But it's usually the hunting group in the end who's mad (the dike destructions and such). Where Delta is truly for the hunters, I've heard on several podcast from Delta higher ups their end goal is more ducks in the sky for the hunters to harvest. I don't think you would ever hear that message from DU. It could upset the environmentalist groups and loose there funding and support.
The predator management part of delta is huge, along with the promotion of the hen house and nesting tube projects.