I'm really fascinated by birds' eyes. The intense red eye of a Bronzed Cowbird, the pale white eye of a White-eyed Vireo, the black-button eye of a Black-crested Titmouse: these features are the first I envision when I think of these birds.
Yes, the eyes have it. Here are some of my favorites:
A Black-crowned Night Heron hides in the back-yard Live Oak tree.
A Green Heron freezes on her nest, as though thinking she's invisible.
A White Ibis's pale iris accents the bright red face.
But it's not birds alone whose eyes fascinate me. Just look at the eye of this American Snout butterfly! Its compound eyes must give it an advantage in finding flowers to feed on. This one is upside-down on a bloom of the fiddlewood beside the front deck. Here's a closeup in case you can't see the eye. 
Now that I think about it, the snout's snout and antennae are every bit as fascinating as that eye! Not to mention its proboscis. I have looked at this photo of the snout butterfly many times since I took it last autumn--but I've always been focused on the eyes and never before noticed the proboscis, or long black feeding tube through which it gets nectar from the flowers.
Which reminds me of one last photograph I want to post: Look at how this female Golden-fronted Woodpecker gets its nectar from the hummingbird feeder. What a tongue! (Click to enlarge the photo if you can't see it.) Though the long tongue is usually used for probing for insects, here it is just as effective at getting nectar.
My camera has helped me see so many details, opening my eyes to nature in ways that not even my binoculars had.
