Last April I was leading a group of beginning birders along a trail beside the Arkansas River, helping them learn to spot and identify some of the dozens of species present on this beautiful spring morning. At one point I heard a distinctive song coming from a thicket: the wichity-wichity-wichity of a male common yellowthroat.
Now, common yellowthroats are indeed common where I live, not to say abundant—but that doesn't mean they're easy to see. These little wood-warblers prefer to stay hidden in dense vegetation, and if they perch within view it's usually for only a couple of seconds before disappearing again.
I pulled out my mobile phone, told the group to gather around, and played a recording of the common yellowthroat song from a bird-watching application I'd downloaded. The male almost immediately hopped up to the limb of a shrub and posed for us, to the accompaniment of oohs and aahs from viewers admiring its bright-yellow breast and black "bandit" mask. Most of the people in the group had never seen a common yellowthroat before, and in fact didn't even know the species existed.