The eastern tiger swallowtail butterfly is the most common of the large butterflies which I have encountered the past several summers, and is unmistakable and therefore an easy ID. These graceful beauties are fairly tolerant – moreso than monarchs, in my experience, and I don’t usually have much trouble getting near enough for a good photo with a telephoto lens.
Their behavior can make a good capture tricky, however. Like all butterflies, they are a bit hyper, moving between blossoms on whims that are difficult to predict. Some of my best interactions come when I meet a swallowtail in a large patch of flowers and am able to track it from a stationary – or nearly so – position.
Of course, like all encounters with the natural world, there are exceptions; the individual pictured above was obsessed with this small cluster of thistle blossoms, which must have been at peak ripeness, and fed on them with little significant movement for an easy fifteen minutes, and was still there when I circled back around a half hour later.