150 years of changes in bird life in Cambridge, Massachusetts from 1860 to 2012

The process of urbanization and its effects on birds has rarely been documented over long time periods. One exception is a bird count started in the 1860s, when the American ornithologist William Brewster first recorded all the bird species on his property in Cambridge, Massachusetts. Since then, invasive species such as the House Sparrow (Passer domesticus) have been introduced, and the site transformed from an estate surrounded by farmland on the rural edge of the city to a residential neighborhood in the inner core of the Boston metropolitan area. We are fortunate to have additional bird species accounts from around 1900, 1940, 1950, and 1960. In 2012 we repeated the bird survey, thus expanding the time series to 150 years. The changes in the bird community over time have been profound and the data contain a wealth of “stories” about how different species and species guilds have coped. The transition from an agricultural to an urban but also more forested system is clearly visible in the records. Overall, species richness has declined from 26 species in the 1860s to just 12 in 2012. However, this is a slight increase from the low point in the 1960s, and there is evidence that some conditions for birds have improved in the last 50 years.