Phenology records around Mohonk Lake date back to the early 1900s, when Daniel and Keith Smiley started noting the date of spring bird arrivals. The Preserve’s Daniel Smiley Research Center continues this tradition of natural history observation and has expanded the scope of the Smileys’ phenology records to monitor seasonal changes in plants and other fauna at Mohonk Preserve on local, regional, and national levels. Alongside our long-term weather data, these data provide insight into the changing communities in the Mohonk Preserve in response to changing climate. These data include first occurrence dates for each of the taxa and associated life stages in the vicinity of Mohonk Preserve and were collected by staff at the Daniel Smiley Research Center.