Welcome to STEM Tuesday: Author Interview, a repeating feature for the last Tuesday of every month. Go Science-Tech-Engineering-Math!
Today we’re interviewing Nancy Castaldo, author of The Wolves and Moose of Isle Royale. The book discusses how restoring the balance between the primary predator and prey was instrumental in restoring a U.S. park’s ecosystem.
This book is a Junior Library Guild Gold Selection and was nominated for a number of awards.
“Castaldo leaves it for reflective readers to decide whether that is responsible conservation or unscientific meddling with natural patterns…Stimulating reading for young naturalists and eco-activists.” – Kirkus (Nonfiction. 10-13).
Christine Taylor-Butler: Hi Nancy. Thanks for letting STEM Tuesday feature you. You are a prolific author on topics related to conservation and nature. Did you always want to be a writer?
Nancy Castaldo: Not professionally. I’ve always loved writing—I was even published in Seventeen Magazine as a teen and entered writing contests—but I never considered it a career path. I actually wanted to work with animals. It wasn’t until my college internship at Audubon Magazine that I realized I could combine my passions—writing, photography, and science—into something meaningful.
CTB: What inspired you to write The Wolves and Moose of Isle Royale: Restoring an Island Ecosystem?
Nancy Castaldo: I first learned about the predator-prey studies on Isle Royale in an undergraduate ecology class, and I was fascinated. I’ve followed the research ever since. When I heard about the recent wolf reintroductions, I knew it was the perfect opportunity to dive deeper and share the story in a book for middle grade readers.
CTB: With the wolf population dropping due to illness and other factors, scientists attempted to relocate twenty to thirty wolves from the mainland.
Nancy Castaldo: Yes. The island is isolated. It’s about fifteen miles from Minnesota and fifty miles from Michigan. In 1980 there were 50 wolves and 664 Moose. By 2018, only 2 wolves remained but the moose population grew to 1,500. So bringing wolves to the island was an attempt to restore the balance.
CTB: How did you gather the information to write about the interactions between wolves and moose?
Nancy Castaldo: I was fortunate to conduct on-site research on Isle Royale alongside wildlife photographer Morgan Heim. It was an incredible experience to spend time with the scientists I’d admired since college. The predator-prey study there is the longest-running of its kind in the world. We met with researchers and park scientists, often traveling by boat and then hiking into the island’s interior to observe their work firsthand. From water chemistry to tracking wolves and moose, we saw just how much goes into understanding this complex ecosystem. Isle Royale is more than just a beautiful place to visit—it’s a living laboratory, and the work done there has implications for ecosystems everywhere.
CTB: Many readers may not realize how important animals are to healthy park ecosystems.
Nancy Castaldo: That’s true. For people like me, wildlife is a big part of why we love national parks. Animals bring the landscape to life—without them, so much of the magic would be missing. On Isle Royale, the wolf and moose populations are a major draw. Visitors are captivated by its wildness and the hauntingly beautiful calls of loons and wolves. The presence of these animals is essential to the health—and appeal—of the park.
CTB: Were there any interesting facts or stories that didn’t make it into the book?
Nancy Castaldo: Always! There are so many stories and facts that just don’t fit into the final manuscript, whether due to space or because they don’t quite align with the narrative. I love sharing those “bonus” details during school visits. It’s fun to give readers a behind-the-scenes look at the research and writing process.
CTB: Do you have any upcoming books we should keep an eye out for?
Nancy Castaldo: Yes! I’m excited to be releasing two new books for young readers this year, both focused on conservation and river recovery. RIVERKEEPER: Protecting an American River and WHALES IN THE CITY highlight real-world successes and show how much we can accomplish when we work together. I’m also thrilled about my first book for adult readers—and curious young adults—coming out next month:
I can’t wait to share all of these new stories with readers!
Nancy Castaldo has written award-winning books about our planet for over 25 years from New York’s Hudson Valley. Her love of reading and writing outdoors began in her childhood. Her curiosity led her to study science. As an environmental educator and photographer, Nancy combined all of her interests. She still enjoys spending her time exploring in the wild as she did while researching over two dozen books and many articles.
Nancy is a certified National Geographic educator and served on the boards of her local Audubon Society and Girl Scout Council. In addition, Nancy serves on the Council of the International Wildlife Coexistence Network and the Writer’s Council of the National Writing Project
Nancy writes to inform, inspire, and empower her readers about the world around them.

Photo by Kecia Stovall