World in a Marsh -- Film Description:
"An intimate view of the miniature cosmos that seethes in a ferment of beauty and savagery behind the tall reeds and in the quiet waters of the marsh. Here strange insects, small amphibious creatures, and birds that prefer watery haunts, devour, and are devoured, according to nature's stern decree of balance and survival of the fittest."
-- National Film Board of Canada

Source:
National Film Board of Canada. "NFB -- World in a Marsh" National Film Board of Canada. http://onf-nfb.gc.ca/en/our-collection/?idfilm=11965.