The northern coast of Java is a very potential area for mangrove and also a place for migratory birds from the Asian mainland. As a habitat for birds, mangroves act as a place to find food (feeding ground), nursery (nursery ground), breed, or just rest. Pulau Dua Nature Reserve is a protected mangrove ecosystem on the northern coast of Java which has become a center for bird activity, so is also known as Bird Island. As a nature reserve, the mangrove ecosystem in Pulau Dua Nature Reserve is considered to be a pristine ecosystem, so this study is important to find out the relationship between mangrove vegetation and the presence of birds. This study aimed to determine the preference of birds in making use of mangrove vegetation, especially in terms of tree canopy parameters which include canopy volume, percent canopy cover, and number of branches.

This study was approached by conducting bird abundance and species inventory using a point count method within a 50 m radius. The inventory was restricted to birds that perch and nest in vegetation, and did not record the birds that were flying over vegetation. Inventory of bird data was classified into three categories based on body size: (1) small birds (<20 cm); (2) medium birds (20–40 cm); and (3) large birds (> 40 cm). Canopy volume data and number of branchings were taken from trees in two 10x10m vegetation plots located inside the bird observation plot. Data on percentage canopy cover were taken at four points in four directions inside the bird observation plots. Results showed that there were different correlations between bird size types and tree canopy parameters. The abundance of small-sized birds is positively correlated with canopy cover percentage(R = 0.868), but negatively correlated with the number of branches (R = –0.706). The abundance of medium-sized birds is only positively correlated with the canopy cover percentage (R = 0.850). The abundance of large-sized birds is positively correlated with the number of branching (R = 0.785), but negatively correlated with canopy cover percentage (R = –0,812). The results of this study can be taken into consideration in rehabilitating degraded mangroves so that they may be conducive to attract birds.