Listen to the sound of the White-throated sparrow here: -- http://www.birds.cornell.edu/programs/AllAboutBirds/BirdGuide/White-throated_Sparrow.html#sound

"The White-throated Sparrow comes in two color forms: white-crowned and tan-crowned. Tan-crowned birds have dull whitish or light tan head stripes, and more brownish chests that usually contain some streaking. In the spring when the sparrow is most brightly colored, most individuals are easily assigned to a color morph. In fall, the morphs are more similar and many birds appear intermediate between the two."

"Although they look nothing alike, the White-throated Sparrow and the Dark-eyed Junco occasionally mate and produce hybrids. The resulting offspring look like grayish, dully marked White-throated Sparrows with white outer tail feathers." -- All info from the Cornell Orthinology website