In the Study of the Gray Partridge and Ring-Necked Pheasant

In the study of the gray partridge and ring-necked pheasant in the United Kingdom, researchers found that gray partridges were declining. A parasitic nematode seemed to negatively affect partridges. The pheasants that carried the parasites were not negatively affected. Researchers performed an experiment in which they allowed both species to feed in one of two enclosures: enclosures with parasite eggs scattered on the floor or enclosures without parasite eggs. The results are shown in the nearby figure. What did the researchers conclude? Was competition occurring, and if so what type?