Changes in Bird Life in Cambridge, Massachusetts from 1860 to 1964

indicate that the changes in the study area reflect those throughout the residential section of the city. The wide scope of changes in bird life similar to those observed in the study area in both North America and Europe over the past 40 years (Wallace 1970, Nisbet 1971) renders this study of general interest that transcends the location and bounds of the study area. Three criteria serve to evaluate and compare the bird life of the study periods. The number of nesting species and the ratio of nesting species to the number that occur as transients during the measure the quantity of breeding birds and evaluate the suitability of the area for breeding. The ratio of insectivorous migratory resident to seed-eating or omnivorous resident species in the nesting population affords a subjective measure of the quality or character of the bird life in contrast to its quantity. Brewster's nomenclature is followed in classifying the birds as summer residents for migratory insectivorous species such as the Gray Catbird and Northern Oriole which are absent in winter, or permanent residents for such seed-eating and omnivorous species as the Common Crow, Blue Jay, House Sparrow, and Starling, which are seen throughout the year. As a rule the nest was found for a bird to be classed as nesting, but birds accompanied by young during the breeding season are included, as the Downy Woodpecker and Purple Finch. Those accompanied by young after the nesting season are classed as transients. Implicit in urbanization is replacement of natural habitat with hous