Environmental determinants of greater flamingo foraging behaviour in an estuarine intertidal sandflat

The impact of flamingo predation on the benthic community has been well researched through the use of caging and exclusion experiments. However, there is still very little known about flamingo spatial foraging preferences and the environmental cues that determine them. The purpose of this study was to investigate the foraging distributions of non-breeding Greater Flamingos (Phoenicopterus ruber roseus) within one of their southern African overwintering grounds, the Heuningnes Estuary. This was achieved by comparing spatial level differences in the abundance and size of flamingo foraging pits across sites and shore positions, and by examining the effects of soil moisture content and sediment profile as environmental cues driving flamingo foraging behaviour. Pit abundance was obtained as a total count per quadrat, and pit size was measured from photographs taken in the field. Sediment cores provided soil moisture content measurements, while sediment profile was measured as the angle of elevation from each shore position to the high water mark. It was found that flamingos fed homogeneously across all four sites, but restricted their foraging to the high shore and upper mid shore regions of the intertidal. Soil moisture content was not a significant driver of flamingo foraging behaviour, but sediment profile was significant. It was proposed that flamingo foraging preference for the high shore and upper mid shore regions was because: (1) the sediment profiles were flatter, (2) the macrofaunal prey densities were greater and (3) these shore positions coincided with the required depth for stamp-feeding, which was linked to the high tide and the time of day at which foraging occurred. This study provides novel information regarding the environmental drivers of Greater Flamingo foraging behaviour and the spatial use of the intertidal sandflats of the Heuningnes Estuary. Furthermore, this knowledge could be useful for the management of flamingo foraging grounds of the De Mond Nature Reserve.

Grantor dc:publisher.institution

Department of Biological Sciences

Year dc:date.issued

2014

Author dc:creator

• Liang, Andrea Yankee

Advisor dc:contributor.advisor

• Pillay, Deena

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/12725

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/12725