Although tidal marsh restoration is occurring on an almost ongoing basis within the San Francisco Estuary, there has been relatively little monitoring of wildlife composition before, during, and after these projects. Monitoring efforts are imperative to understanding the effects of habitat enhancement efforts on the population dynamics and densities of wildlife, which can be especially important when it comes to special-status species. During the initial planning phases of a potential wetland enhancement project, Marin County partnered with WRA, Inc. to plan and implement a preliminary small mammal study, with a focus on the endangered salt marsh harvest mouse (Reithrodontomys raviventris; SMHM). The study area, McInnis Marsh, is a well connected, moderately sized marsh consisting of diked and tidal wetlands. Monitoring has occurred each spring and fall between 2020 and 2023 and across those years precipitation has been highly variable. Results were somewhat unexpected, often with much higher captures of SMHM in the ostensibly low quality diked wetlands, dominated by invasive plants, than the pickleweed-dominated tidal wetlands. There were also shifts in patterns of SMHM captures in response to variable precipitation. These results have provided valuable insights and influenced the planning process, demonstrating the value of comprehensive pre-project monitoring.