This article describes a preservice teacher training in line with meeting the Common Core State Standards for Mathematics (CCSSM) using geometric reasoning, spatial sense, measurement, representation, communication, and problem solving. The author infers that when preservice teachers lack pedagogical content knowledge they cannot successfully translate this competence for teaching content with meaning. Teachers with weak pedagogical content knowledge will fail to plan meaningful lessons or anticipate areas where students might struggle; they will be unprepared to answer students' questions or detect students' misconceptions; and, inevitably, their students may acquire distorted meanings. In response to this challenge the author explored the impact of a bird house nesting box activity on participants' geometric subject matter knowledge. The nesting box task integrated across mathematical domains (number and operations, algebraic thinking, measurement, and geometry) and across subject areas (ornithology, the scientific study of birds; flight, geography, migration; state birds; art; music; and carpentry). Preservice teachers can take these idea with them into student teaching placements and future classrooms.