The exotic Smooth Cordgrass (Spartina alterniflora) has spread rapidly on the east coast of China over the past three decades and has greatly changed the native saltmarsh vegetation. We conducted bird surveys using mist nets in the exotic Spartina and native Common Reed (Phragmites australis) habitats at Chongming Dongtan of eastern China in the winters of 2004 and 2005. We related bird capture rates to habitat type (Phragmites or Spartina habitat), habitat structure (plant height and density), and food availability (densities of seeds and arthropods). The Spartina habitat was composed of shorter and denser vegetation and provided fewer food resources for birds than the Phragmites habitat. Bird capture rate was lower in Spartina, negatively related to plant density in the Spartina habitat, and positively correlated with overall arthropod abundance and plant height. Food resources consumed by birds were similar to those found in Phragmites habitat, irrespective of capture location. Our results suggest that the alteration of habitat structure and reduction in food resources are probably the proximate causes of lower avian species richness and relative abundance in the exotic Spartina than in the Phragmites habitat at Chongming Dongtan.