I have previously described this calibration as "gyro calibration", but it is in fact calibration of the on-board compass. However, if you have not flown your bird for a while, then this is definitely what you want to do.
To calibrate the gyros, you only need to hold the left stick up and to the left. You must do this before the motors will start.
Two other things you will want to do on a bird that has not been flown in a LONG time are:
1) Re-calibrate 'level'. Set the MOTORS (all four of them) as level as possible and then hold the left stick up-and-right. You will hear a beep. You really want to get this right, because this is the 'attitude' that the bird will always try to return to, so if it is off even by a few degrees, then you will find that the bird wanders a bit.
2) Plug in the battery and just let it sit outside for a while. The battery will last quite a while with the motors not running. Doing this will re-charge the GPS's battery, while also letting the GPS rebuild the satellite almanac. Some very strange behavior will be realized if you lose GPS lock while flying!!
Please note that if you have upgraded to the latest firmware, the compass calibration process has changed dramatically AND the bird is FAR more reliant upon the compass in the latest firmware version. If this is the case, let me know!
