Hairstreaks, at least the few I've found so far, are little fast butterflies with similar features. You have to really know your butterflies to be able to tell them apart on the fly. Tim Adams helped me identify my first Gray Hairstreaks. Thanks Tim!

Gray Hairstreaks have cute thread-like tails that wriggle like fish bait on the line. Those tails appear to work like fish bait too.

The small hairstreak butterfly above is missing it's tails; they're just nubs now. The gray hairstreak perched on the Spanish Needles Plant on the right has a bite missing out of it's wing just below the longer tails.

Here's a closer look at the bitten butterfly wing:

A little lower, and this butterfly would have been dinner. Perhaps those little tails distracted it's predator just enough to save it.

This gray hairstreak butterfly has all of it's tails intact, waving prettily in the air.

You can look at a smaller, but similar hairstreak here: Red-banded or Gray Hairstreak