Lark sparrow
Chapter 3: Why and How Birds Sing
Subchapter: Courtship songs
From page 32 in the book.
♫96. Normal song, rich and thrilling, one of the finest sparrow songs in North America. April 6, 2013. Chaparral Wildlife Management Area, Artesia Wells, Texas. (5:06)
♫97. Courtship song, gushed in muted tones, continuously whispered, it seems, directly into her ear. April 24, 2013. Kerr Wildlife Management Area, Hunt, Texas. (1:04)