Great butt-kicker. Definitely the most challenging hike I've done anywhere around the valley. Surprisingly, trail above falls was not as crowded as we expected for a Sunday afternoon. Weather was perfect in the mid-70s. Hike/scramble/climb up to the Flat Iron was challenging, tiring and very rewarding. Almost as rewarding as the beer and burger that followed. California Poppies beginning to bloom down in the basin. On the hike down we heard some crazy, loud, repeating woodpecker-sheep-like sound echoing from the canyon below. Eventually located the source and found it to be a very small (about 2") toad in the small pool at the bottom of the large trickling water fall. Couldn't believe how loud and odd sounding that tiny little toad was.