Hunting for Frogs on Elston: And Other Tales from Field and Street is a collection of the best of Jerry Sullivan’s Field & Street columns, which were originally published in the Chicago Reader. The essays are short and touch on a range of topics, including prairie restoration, the changing seasons, birding, and the people who have contributed to our understanding of Chicago’s nature. But one of the essays in particular has stayed with me. Indeed, it is one phrase in that one essay that I keep repeating in my head. That phrase is: witness trees.