Observations by local naturalists may provide valuable records of phenological events with which we can measure the response of species to climate change. To test this idea, we examined the records of a dedicated naturalist who has been observing bird arrivals, plant flowering, butterfly appearance, and frog calling on her farm in Middleborough, southeastern Massachusetts. From her 1970 to 2002 records, we extracted data on first observations of spring phenological events for 24 species—650 observations in all. Over that time, average annual local temperatures rose by 2.0° C. Twenty-two species showed earlier activity, with 5 of the 16 bird species now arriving significantly earlier in the year than they did 30 years ago. Twenty-two species responded to warming temperatures, with 4 species (two birds, one frog, and one plant) showing statistically significant earlier activity in years with warmer temperatures. The other 18 species showed similar trends, but they were not statistically significant.