Why do birds have bipedal locomotion?

Birds belong to the class of Aves in the phylum Vertebrata.

As an adaptation to the aerial mode of living, their body shows many modifications. They bear feather-clad wings which are modified forelimbs. The wings help them to fly in the air.

Since forelimbs are unavailable, birds use their hindlimbs for walking and perching. This mode of locomotion is called bipedal locomotion.