The Haders were early champions of conservation, animal protection, and pacifism. This made its way into their work, particularly with titles such as "The Runaways" (1956) and "Two Is Company, Three's a Crowd" (1965?). In the early 1950s, Berta became a community activist, ignited by the seemingly lost cause of having the location of the proposed Tappan Zee Bridge moved to a less sensitive area than its planned path through her village. Though "The New York Times" accused her of "blocking progress," the New York State Thruway Authority eventually relented, and the massive 4,88 km-long bridge was built several kilometers to the north at Nyack, where the bridge still stands today.