(Setting up a tripod and camera in underbrush nearby) is a way to be ready when the animals come. The phrase between brackets is a/an

The phrase between brackets is a gerund phrase.

Explanation:

A gerund is a verb form that can function as a noun in a sentence. It is the '-ing' form of the verb that identifies as a noun.

A gerund phrase is a group of words that starts with a gerund and contains modifiers, nouns, or pronouns that acts as a direct object or can act as the subject in the sentence.

In the given sentence, the words in the brackets is a gerund phrase. It starts with the '-ing' form of the verb.