The nature preserve was wonderful. You feel like you are in the brush. We opted for the shuttle bus tour. The driver was very knowledgable and made numerous stops to observe various species of birds and animals. We walked along a boardwalk listening to explanations of how the eco system works. An added bonus was observing the flying fish.
ONE MAJOR WARNING: Take bug repellent. There are little bugs (locally called "no-see-ums" for obvious reasons. They bite multiple times and those bites can be painful as one in our party found out). Having said that, Darling NWR is worth the visit.