My rule in birding is that I must photograph the bird well before I can count it on my observations. I've heard the Crissal Thrashers and Virginia Rails before but couldn't count a single one until I got my eye on the bird!
My ear is good at picking up the slightest sounds. The voice of the Sora is unmistakable and yet it is rarely seen! The Virginia Rail is the same! The Crissal Thrasher sings its elaborate song early in the morning. The minute you get close enough to get a decent shot, it drops to the ground.
Curve-bills are completely different. They'll sit and look you in the eye. But not the Crissal Thrasher.
On an outing to Whitewater Draw, my greatest dreams came true as a Virginia Rail was seen out in the open. This is a very rare thing! I was with another photographer at the time and we focused our cameras on this bird instead of the hundreds of Snow Geese flying over our heads. Most photographers in the area were snapping shots of the geese but when a rail makes a grand entrance, you drop everything you're doing and get pics!
The Treecreeper is hard to get a focus on as it matches with the bark of the tree. Many times this bird will blur into the bark. Very frustrating!
When these rare moments occur; complete focus happens.