Eastern Bluebirds sing a fairly low-pitched, warbling song made up of several phrases, each consisting of 1-3 short notes. Harsher chattering notes may be interspersed with the whistles. The whole song lasts about 2 seconds. Typically, unpaired males sing this song from a high perch or sometimes in flight, as they try to attract a mate. Females sometimes sing this song when they see predators on their territory. Paired males sometimes sing a much softer version of this song while females are laying eggs.
The Eastern Bluebird’s most common call is a soft, low-pitched tu-a-wee with a querulous tone. The call lasts a little less than a second, with males’ calls typically slightly longer than females’. Bluebirds give this song in all seasons as a way of keeping in touch with each other or to signal nestlings that adults are bringing food. When bluebirds get too close to each other, they let each other know with a single, harsh screech. Females make a very soft, low chip when a courting male approaches. Birds nervous at the approach of a ground predator make a loud, continual chit-chit-chit.
Bluebirds attacking predators or other intruders on their territory may dive-bomb them and clack their bills shut.