The Field Sparrow’s most familiar song is a long, accelerating series of short whistles that build to a rapid trill. It lasts about 4 seconds and has the quality of a bouncing ball coming to rest. In early morning, males sing a more complex song, which begins with the trill followed by longer notes, and is used during territorial interactions.
Males and females both give an array of calls, including a single-note “seep” when foraging together, and a higher-pitched version made by mated pairs when courting and nest building. A brooding female makes a call that sounds like a low-pitched cricket’s chirp when her mate approaches the nest with food. Threats will elicit a chip call, possibly to alert a mate or chicks, and the birds will react to hawks with a high, thin, whistled zeeeeee.