I have been using a very narrow definition of "common", but after chatting with our awesome moderator, I'm going to start broadening that so I can post more! Currently I am in Hawai'i, and on Friday I went on a hike at 'Anaeho'omalu. Now, I do not live in Hawai'i, so this is not "common" for me, but it is a readily available hike for most Big Island residents--free, unrestricted access, and not too long (although it does go along a sandy beach and over a lot of rough cobbles, so is not very accessible for people with mobility issues).

The very best thing, in my opinion, is the abundance of Green Sea Turtles (Chelonia mydas), who not only feed along the shoreline, but lie on the beach in the sun for hours, generally uncaring of people staring at them a lot and taking photos (you can tell the locals because they are not so fascinated by the turtles; I cannot imagine not being fascinated by the turtles):



The turtles leave tracks in the sand from hauling themselves along with their front flippers:



There are also gorgeous, tiny, cryptically camouflaged ghost crabs (Ocypode sp.):



Beach Naupaka (Scaevola taccada syn. sericea):



Fields of black pāhoehoe basalt:



Petroglyphs:



And native shorebirds like Pacific Golden Plover (Pluvialis fulva) and Black-crowned Night Heron (Nycticorax nycticorax):





We spent about 3 or 4 hours on the hike, going very slowly and pausing to look for fish, photograph ALL the turtles, and wade in the water. More pictures here.