The northern cardinal produces at least 16 different calls, but the most common call is a loud, metallic chip. It is used when predators are in the area and to warn intruders to leave.
Females use this call when they approach the nest. Both males and females use it when bringing food to the nest and when encouraging their young to venture out of the nest.
In addition to making calls, male and female northern cardinals sing in clear, whistled phrases. Their songs last two or three seconds. Northern cardinals mainly sing in the spring and early summer, but the males especially are likely to sing throughout the year.