In March, our White Throated Sparrows and Juncos begin heading north to their breeding grounds, and our Song Sparrows begin arriving from their winter haunts somewhat further south in the US.
The ground-feeding Song Sparrow can be seen throughout the US. The tweety mating call of the male in Spring (here) is familiar to everybody who steps outdoors.
It is theorized that the guy with the best song gets the hottest chicks.