Look for spotting scopes!
If there is a crowd of people pulled over on the side of the road or you see people with spotting scopes, chances are there is wildlife to see! People are friendly and will often point out where/what they are looking at. I recommend bringing your own pair of binoculars to help see animals as well. If you do decide to pull over, make sure your car is completely off the road as to not cause a traffic back up.
Go check out my guide for the best free things to do as well as itineraries and travel tips to make your trip unforgettable.