Fig 1.
Distribution of sampling locations across the Fraser Estuary—Boundary Bay migratory stopover location, 23 April–7 May 2012.
Fig 2.
Mean isotope values of δ13C and δ15N (± standard deviation) for microphytobenthos, small invertebrates, large polychaetes, surface sediments (biofilm) and Western Sandpiper droppings.
Samples were collected at eight study sites within the Fraser Estuary—Boundary Bay migratory stopover location, 23 April–7 May 2012. 1:a Mud Bay, 1:b Boundary Bay East, 2:c Roberts Bank Inter-causeway, 2:d Roberts Bank Brunswick Point, 2:e Roberts Bank Westham Island, 3:f Sturgeon Bank South, 3:g Sturgeon Bank North, and 3:h Sturgeon Bank Iona.
Table 1.
Estimated contributions of surface sediments (biofilm), small invertebrates and large polychaetes in Western Sandpiper droppings across the Fraser Estuary—Boundary Bay migratory stopover location, 23 April—1 May 2012.
Fig 3.
Proportion of large polychaetes, small invertebrates and surface sediment (biofilm) in Western Sandpiper diet based on dropping and prey samples collected during spring migration (23 April–7 May 2012).
A three source mixing model of δ13C and δ15N was used for eight study sites within the Fraser Estuary—Boundary Bay migratory stopover location: 1:a Mud Bay, 1:b Boundary Bay East, 2:c Roberts Ban: Inter-causeway, 2:d Roberts Bank Brunswick Point, 2:e Roberts Bank Westham Island, 3:f Sturgeon Bank South, 3:g Sturgeon Bank North, and 3:h Sturgeon Bank Iona.
Table 2.
Bhattacharyya’s Coefficient (BC) for pairwise comparisons of estimated diet of Western Sandpipers at study sites within the Fraser Estuary—Boundary Bay migratory stopover location.
Table 3.
Average total counts, and average estimated proportions of Western Sandpiper (WESA) and Dunlin (DUNL) from ratios in sample flocks within study sites in the Fraser Estuary—Boundary Bay migratory stopover location, 23 April–1 May 2012.
Fig 4.
Average proportions of Western Sandpiper and Dunlin in all flocks of birds differentiated to species, in study sites or areas that exhibited significant differences in diet composition.
Site 1a: Mud Bay (n = 1), Site 1b: Boundary Bay East (n = 6), Area 2: Roberts Bank (n = 8), and Area 3: Sturgeon Bank (n = 3).