We never used to get White-crowned Sparrows in our yard, but for the last 5 years or so they’ve been coming through every spring and fall during migration season.
I love listening to these birds sing, and the first year one arrived in my yard it took me weeks to figure out what bird was singing from the shrub next to my window.
Fun fact (courtesy of the Cornell Lab of Ornithology’s All About Birds website): “The song of the White-crowned Sparrow Is one of the most-studied sounds in all of animal behavior. Different subspecies across the country sing clearly different songs, but they’re all recognizable by the sweet, whistling introduction, a succession of jumbled whistles, and a buzz or trill near the end. Songs last 2-3 seconds. Females sing only rarely.”
“Because male White-crowned Sparrows learn the songs they grow up with and typically breed close to where they were raised, song dialects frequently form. Males on the edge of two dialects may be bilingual and able to sing both dialects.”