Final answer:
The error in the sentence is the use of 'female's' that erroneously suggests possession instead of the correct plural form 'females'.
Step-by-step explanation:
The plural or possessive error in the sentence is found in the segment "the brown female's blend into their environment." It should use the plural form "females" instead of the possessive form "female's" since we are talking about more than one female pheasant blending in. This aligns with the rule to add ['s] to the singular form to indicate possession, and simply an "s" to form the plural when there is no ownership. So, the correct sentence should be:
Male ring-necked pheasants' copper and gold coloring makes them stand out in the wild, while the brown females blend into their environment.