Larry, you are right. I shouldn't include endangered fish research, etc., when we are talking about wildlife conservation.  However, according to the same link, $307 million was spent in 2012 on acquiring conservation critical habitats.  Still way more than the $200 million of federal excise tax on sale of guns and ammo you cited.  And you're ignoring the fact that much of the federal excise tax comes from sales of guns and ammo not used in hunting, for example most handguns purchased for personal defense.

Ducks Unlimited is a great organization.  Still doesn't come close to matching the money the feds and states spend on non-hunter-specific wildlife management, mostly from income or corporate taxes.