Males string together husky, whispering trills, slurs, and short ascending notes into songs lasting 3–13 seconds. Songs are generally more nasal or wheezy than those of other finches. Song phrases are sometimes punctuated by "watch-winding" or "churry" notes (see Calls Description). Adult males can continue to add songs to their repertoires.
Pine Siskin flocks are constantly atwitter with wheezy contact calls while feeding or in flight. Their most recognizable call is a "watch-winding" note, a harsh, upsweeping zreeeeeeet lasting most of a second, tossed in amidst shorter calls. They utter a distinctive flight call, an explosive zwee or psee that initiates startled flight. In flight, a tit-a-tit call often accompanies each flap-and-glide undulation. A single siskin can call back the flock with a solitary note. Females solicit copulation by uttering soft calls while bowing and fluttering tail and wing feathers. The female solicits feeding from the male with a low twittering call that carries well through the trees.