As one becomes a better birder, sound becomes a increasingly important factor in locating birds.
Yesterday, I got out of the car at one of my favorite birding spots and heard a squeak wheel type song coming from a near by pond. When I got to the pond . . . the song was coming from up on a connecting hill. Eventually I saw our carnivorous song bird the Northern Shrike vocalizing. First time I’ve heard one sing.
A few minutes later I followed a rattle to Belted Kingfisher and then some angry crows to a Red-tailed Hawk.