Answer: The appositive phrase is "a nocturnal hunter".
Step-by-step explanation: An appositive phrase is a phrase that renames a noun or another noun phrase that is next to it. Moreover, an appositive phrase can be restrictive or nonrestrictive. It is considered to be restrictive when it is not separated from the noun or noun phrase that renames with commas, while it is nonrestrictive when the phrase is separated from the rest of the sentence with commas. In the sentence provided, the appositive phrase is "a nocturnal hunter" because it is renaming the noun phrase "the kit fox" and providing additional information about it. Moreover, it is a nonrestrictive appositive phrase because it is separated from the rest of the sentence with commas.