From the CCO Operations Manual, Section 5.11
Should one of the Club Slide Competitions be a Nature Competition, the competition rules and topic definition shall be as is outlined below. All other rules of the competition shall apply except that, in addition to any Awards of Excellence or Honourable Mention awards, one award shall be made for the best entry. This last award shall be kept confidential, to be announced at the Annual Awards Ceremony with the presentation of the Best Nature Slide trophy.
Entries may include any naturally occurring substance or substances, for example land, sea, air, plant, mineral, animal, but may not include human beings nor the evidence of human beings as in a house, fence, wire or domesticated animals (tagged wild animals are, however, allowable). The unobtrusive evidence of human beings will only be allowed where if associated with a species’ normal habitat; for example a barn swallow at its nest in a farm building.