I try to introduce research starting in Kindergarten and have the students start working on it on their own by the end of Kindergarten or beginning of first grade, often it depends on if the teachers want to do projects and what my schedule looks like as far as how much flex time we have. I usually use this 3-2-1 format (3 facts, 2 questions, and 1 thing most interesting) with my 1st graders to start out with. It encourages them to find information, brainstorm questions, and can be applied to any topic.
We usually do it together the first time about crocodiles (Caleb the Ctoc is our school mascot). The next week, I pull some 1st grade level books about various animals. With a partner, they choose a book and complete the 3-2-1 on their own the following week. We also practice adding the title and author and start talking about citations and sources.
Here are a couple of the ones they completed just before Christmas.