Song Sparrows are the virtuosos of the sparrow family. As with most birds, song is used to attract mates and defend territory. Studies show that the female Song Sparrow prefers the more learned virtuoso, the one able to reproduce a matched sound from his teacher.
Breeding birds in North American typically use the length of day to determine the cue for when to come into breeding condition. However, Song Sparrows also include temperature in determining the cue. Studies found that Song Sparrows living at the same latitude, but different elevations, bred at different times. Obviously, Song Sparrows living in warmer temperatures where trees were budding out sooner, started breeding sooner. Surprisingly, as much as two months earlier.