Make a rapid clicking sound with your tongue when you get close to the cage. This is a sound they make to welcome each other, you may notice if one's in the pouch and another wants to come in they'll often make the click-hiss-honk. We can't make the exact same sound, but my boys seem to understand my "Pidgen Glider" and appreciate it. (I also do the hiss tolerably well, but can't get the honk.)