While practicing emergency landing techniques in a C152 the aircraft was struck on the vertical stabilizer by an object; possibly a bird.

Narrative

I was demonstrating an emergency approach to land in a simulated mountainous area; selecting a clearing between two tree lines. On final approach I allowed the aircraft to descend below 500' AGL 'Over other than congested areas.' Upon recovery; with full power applied; I heard the noise of an object striking the aircraft. I checked performance; preparing to land in the clearing. Noticing that the climb performance was normal and flight controls were fully functional; I proceeded to my destination; notifying maintenance and owner. The vertical stabilizer was struck and damaged. It may have been a bird; but is missing the normal blood and debris. There were no noted structures; tension lines; and etcetera. Perception of the area was that it was sparsely populated with no noted structures. Judgment to perform the maneuver in this location was based on familiarity of the area. However; the nearby river is currently flooded over the fields leading to a different appearance of the terrain and this lead to the decision to perform this maneuver two miles north of where I normally perform it. The decision to descend below 500' AGL was most likely the cause of the occurrence.