I had Crossbills songs and calls already loaded onto my mp3 player, and had that hooked up to the car radio. Not hearing any response, I walked off a distance from the car, and thought I heard a call, but it was hard to be sure with the calls playing in the background, so I signalled to my mom to turn off the mp3 player. I listened. Nothing. I walked on a bit more, a bit disappointed and thinking of going home. Then I heard it again. It sounded like just snatches here and there of the song file I had, but I didn't want to get my hopes up and go looking for a bird that wasn't actually there, so I mentally bookmarked my location and went back to the car. After confirming that the mp3 player was indeed off, I returned to my previous location, listened, and heard it again. Now would be the tricky part of actually finding the birds. I couldn't pinpoint the sound due to moderate traffic on a close road, and I was surrounded by several pine trees, each quite volumous. I scanned a few tree tops with the binoculars and then spotted a flutter of wings as one of the Crossbills--a male--moved to another branch.
I followed them from tree to tree and finally got a glimpse of a few females.
Just as I was thinking I should probably leave (as my sister was probably getting tired of sitting in the car) they started flying down in groups of 3-5 to drink from a puddle about 5 feet in front of me!