Behavioral evidence of the role of lumbosacral anatomical specializations in pigeons in maintaining balance during terrestrial locomotion.

In birds there are anatomical specializations in the lumbosacral vertebrae and spinal cord. These include segmentally organized bony canals which are related to accessory lobes of the spinal cord. Both structures are connected by cerebrospinal fluid. To test whether these specializations function as a sense organ of equilibrium the effect of opening the fluid space was studied in pigeons. Locomotory behaviors on the ground (landing on a perch, keeping balance on a rotating perch, walking) but not flight were significantly impaired after lesion. These results support the assumption that the lumbosacral specializations are involved in the control of locomotion on the ground.