Shorebird Feed

Shorebird feed

from the above it is clear that the physical composition of the sediment influences the numbers of shorebirds feeding upon it, but within a suitable area of mud it still known precisely what attracts birds to one part of a beach and not to another. there are clues, however. small ocypode crabs, prawns, fish larvae, polychaete worms and small bivalves are among the most important foods for shorebirds and the distribution of these foods between beaches is very uneven. Differences in the fauna in mudflats can really only be determined by direct investigation (Swennen and Marteijn 1985). where suitable prey is present, density is the most important factor, followed by prey size, prey depth and the penetrability of the substrate (Myers 1980).

Tidal state, wind and disturbance all affect the density and availability of prey, and this is why certain beaches are only used by the waders at certain times (Evans 1976; Grant 1984). Casts of mud thrown up by susupension feeders and swimming movements of small crustaceans are visual clues for the birds, showing them where to feed (Pienkowski 1983), but some birds use tactile rather visual clues and have sensitive beak tips which can sense prey underground. Sandpipers, one group of partially tactile feeders, may avoid sandy mud because the sand grains are very similar in size to the polychet and oligochaete worms upon which they feed (0,5-1 mm) (Quemmen 1982).

Shorebirds in Celebes

Shorebirds in Celebes
In addition to four species of resident shorebirds, at least 34 migratory species visit Celebes coasts twice each year. They can be seen between February and april and between September and November, on their way to and from their breeding grounds in northeastern and eastern asia and their wintering grounds possibly in northwestern Australia (white 1975). Between February and april and returns between September and November. These birds would most often be encountered on muddy rather than sandy shores.

Very little is known about the movements of these birds within Indonesia and the basic questions posed thirty years ago have barely begun to be answered. That is: what are the normal migration routes? How many birds are there (commons de ruiter 1954)? Ornithologist from interwader, an international shorebird study programme, during the first part of 1986, and two areas of mudflat were visited: the north of bone bay, and the coast north and south of watampone.

The northern site had extensive mangroves but the mud was rather sandy and, therefore, not especially suitable for waders. One exception was the muddy estuary of the balease river where at least 18 species were seen, four of which constituted about half of the total number of birds seen. The coasts around watampone were found to have less sand than in the north, and the shorebirds were consequently more common though of fewer species (Uttley 1986).

Source: Ecology of sulawesi 2002