When I first tried to learn butterflies, their wings confused me so much I often just gave up. Big, showy butterflies were not-too-tough to identify (most of the time), but smaller, more subtly-colored butterflies like these two seemed impossible.
I had been spoiled by birds, whose wings are easy to understand and are rarely the sole means to an ID. Birds show us bill shapes, head patterns, feet structure, and lots else to help us name them (and birds have voices as well!). Butterflies generally must be identified by their wing patterns alone, and they have four wings (not two). Putting a name to a butterfly requires that you understand how the wings fit together and which of its eight wing surfaces the insect is showing you at any moment.
Adding to my confusion were the insect and butterfly field guides at the time, which generally illustrated butterflies as pinned specimens, with their wings held wide — in postures you do not see in the field. Butterflying has become much more fun in the last 15-20 years with the publication of more than a dozen field guides filled with photos of living butterflies, to be identified by field marks you can spot through binoculars or by stepping close. And digital photography now allows do-it-yourself, leisurely analysis back home: snap a shot in the field, blow it up on your PC afterwards, and study for as long as you like.
The two butterflies here, nectaring on an aster on 9/29/10 along Pomona Road, are eastern tailed blues, Everes comnytas. They are small — in profile about the size of a penny — but if you crouch or kneel down nearby, and do not block the sunlight, they often let you study them at very close range.
Click on the photo above and study the wing patterns.
The individual on the right is showing the underside of two wings: the underside forewing, straight-up from the head, mostly grayish with some darker spots and lines, and the underside hindwing with a couple of pretty, orange crescents. Look close and you can also see the “tails,” sticking out just beyond the crescents. The tails and those crescents give you the ID.
To understand why this creature is called a “blue” you must look closely at the second individual — and focus between the wings. There you can just make out the upper surface of all four wings. If you see one of these butterflies flying around your feet, you’ll see those upper surfaces flash blue in the sunlight. They almost always fold that blue away from sight as soon as they land, however — probably as protection against sharp-eyed birds.
Here’s a photo from a couple of years ago when I lucked into….