| Between June 2006 and October 2007, the birds and avifauna in the area of Hangzhou had been surveyed using line transects on 657 transect routes, each 3km in length and 100m in width, about 4km apart. We divided habitats of all transect routes into 5 types of habitats, urban area, rural-urban continuum area, farmland area, forestland mixed area and forestland area, based on urbanization level across an urban gradient, and surveyed the bird species diversity and the avian nesting guilds/functional groups on the 90 routes (18 routes for each type of habitats) selected from all transect routes in between March 2007 and August 2007 in order to know the effects of urbanization on bird species diversity and community, including the responses of avian nesting guilds, species diversity and functional diversity to the urbanization and its causes, the factors influenced the distribution of avian nesting guilds and the relationship between functional diversity and species diversity across the urban gradient. The results showed as follows:(1) 224 bird species, belonging to 16 orders 46 families, were recorded in our surveys in Hangzhou. Based on the records of our surveys and the former records of avifauna of Hangzhou,354 bird species, belonging to 17 orders 66 families, have been recorded totally. Among these species, there were 191 Palaearctic bird species, 154 Oriental bird species and 9 widespread bird species. The avifauna of Hangzhou has the feature of transiting from Oriental realm and Palaearctic realm in bird composition.(2) 96 bird species were recorded on the 90 routes located in the 5 type habitats with different urbanization levels. Based on the locations of the nest sites, all bird species could be classified as 9 the nesting guilds, i.e. canopy nesters, shrubs nesters, canopy/ shrub nesters, natural cavity nesters, buildings nesters, natural cavity/ buildings nesters, ground nesters, water surface nesters and parasite nesters.(3) The numbers of the nesting guilds and the species in nesting guilds both declined with increased urbanization. We found that the urbanization had different impact patterns for different nesting guilds. For example, the number of canopy nesters, shrub nesters, ground nesters and natural cavity nesters declined with increased urbanization. Shrub nesters and ground nesters were particularly more sensitive to urbanization. For the natural cavity/build nesters, numbers increased with urbanization. The affecting patterns of urbanization were different with different nesting guilds as they using different nest-sites.(4) Although all of variables of habitat measured in our survey, the vegetation coverage, areas of buildings and distance to the city center and human disturbance could influence the avian community structure of nesting guilds, each variable had a specific pattern of the effect on the nesting guilds separately.(5) The urbanization could decrease both species richness and species diversity. We did not find a peak of diversity at the moderate urbanization area. Maybe the more intense of urbanization and disturbance in this area frustrated the advantage of urbanization.(6) The urbanization could decrease both functional richness and functional diversity. The decreasing of nesting resources might cause this.(7) Both functional diversity and species diversity were adversely affected by increased urbanization, but their patterns were different. The form of the relationship between species diversity and urbanization was a line, but the relationship between functional diversity and urbanization was a quadratic function curve. It meant that the functional diversity was insensitive at low urbanization levels, but dropped dramatically at high urbanization levels. The quadratic function curve of the relationship pattern between functional diversity and species diversity also suggested that a linear relationship between functional diversity and species diversity could exist only at low diversity levels across the urban gradient.
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