Birding is one of the many popular activities in the National Park System, and by carrying your binoculars and perhaps a field guide to help you identify what you see, you quickly can expand your "life list" during a park visit.

Which has us wondering: If you're a birder, where in the system do you go, and what are you looking for?

When I saw what I thought was a cardinal perched high atop a cactus in Saguaro National Park, I knew I had to get a photograph so I could figure out exactly what I had seen. While I didn't have a powerful enough lens to get a good sharp image, it was good enough that when I studied the photo, and did some quick research on the park's web site, it became obvious that I had seen a Pyrrhuloxia, a relative of the Northern Cardinal.

Along with the Pyrrhuloxia (and road runners that dashed across the grounds of our accommodations just outside the park), I've seen bald eagles, trumpeter swans, sandhill cranes, pelicans, Clark's nutcrackers, and pine grosbeaks in Yellowstone National Park, osprey, swans, and pelicans in Grand Teton National Park, canyon wrens and Western tanagers in Canyonlands, condors in Grand Canyon National Park, and listened and watched as nighthawks danced in the evening skies as they chased insects above the Yampa River in Dinosaur National Monument.

And that's just what I can recall off the top of my head.

While I doubt I'll ever see an ivory-billed woodpecker, an incredibly rare bird long considered extinct until one was seen in 2004 in Cache River National Wildlife Refuge in Arkansas, some birders hold out hope that others will be seen, possibly in Congaree National Park in South Carolina or Big Thicket National Preserve in Texas.

So, which parks do you like to go birding in, and what do you hope to see? Have you spotted any particularly rare birds, and if so, which ones and where?