The study sites were thirteen mangrove patches in the Darwin Region [34]. The area of mangrove at
each site was estimated from satellite photographs (1994 QuickBird satellite image–pan-sharpened
60 cm resolution) using ArcGIS 9.3. Birds were census using the variable width line transect method [35].
Transect were walked twice a month at all sites from February 2008 to May 2009. Birds passing
overhead (commuter species) and all seabirds and migratory waders were excluded from the analysis.
Species were assigned to six different functional groups defined by Sekercioglu [36]. Seventy species
were classified in this way with some species assigned to more than one functional group. Many bird
species found in mangroves are also temporary residents of adjacent habitats and similar habitats further
inland [7,37]. Mangrove dependent species (MDS) were defined in this study as those species that were
relatively restricted to mangroves and that spent most of their foraging time in mangroves (or were
uncommon or absent from other habitats) and that usually nested in mangroves; on this basis MDS were
identified from Noske [32]. Species that were observed only well within mangrove patches were
classified as “interior” species; this excluded species at mangrove edges and those that also used the
matrices. Bird diversity, abundance and density estimation have been described in Mohd-Azlan et al. [33].