Here’s some advice that we wish we’d follow more often: bring your spotting scope when you’re hiking. It seems that every time you decide to leave the scope in the trunk, a cool looking bird is just a bit beyond your binocular view and sits for a long period of time, usually across the lake or other impossible-to-cross barrier.
So when in doubt, lug the scope and tripod along just in case. It might be difficult to manage with your camera, backpack, GPS, and whatever other gear you have along, but the rewards are almost always worth it.
There are special scope-carrying backpacks that make bringing your scope on hikes much easier. One type can be found at the American Birding Association.