Both male and female Northern Cardinals sing. The song is a loud string of clear down-slurred or two-parted whistles, often speeding up and ending in a slow trill. The songs typically last 2 to 3 seconds. Syllables can sound like the bird is singing cheer, cheer, cheer or birdie, birdie, birdie. Males in particular may sing throughout the year, though the peak of singing is in spring and early summer.
Scientists have described at least 16 different calls for the Northern Cardinal, but the one you’ll hear most commonly is a loud, metallic chip. Cardinals make this call when warning off intruders to their territory, when predators are near, as females approach their nests, and by both sexes as they carry food to the nest or when trying to get nestlings to leave the nest. When one member of a pair is about to feed the other, either bird may make a softer took note.