Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. https://www.hindigyanvishv.com/best-catch-Sunjoy-9-x-11-Foot-Arched-Pergola-Cover-Backyard-Roof-Canopy-Tent-For-Parts-p29332-mega-find/