The pilot was landing the tailwheel aircraft in gusty winds that were shifting direction. He touched down on the main gear with a headwind, but as he lowered the tail to the runway surface, the aircraft was hit with a crosswind that caused it to swerve toward the side of the runway. Although the pilot attempted to realign the aircraft with the runway, it departed the left side of the runway and impacted an earthen berm. Upon contacting the berm, both main gear collapsed.