1977_Populations, biomass and food habits of ducks on the Fraser Delta intertidal area BC

The Fraser Delta intertidal region consists chiefly o f three extensive tidal flats (Figure 1): Sturgeon and Roberts Banks, together also referred to as the Fraser Delta foreshore, and Boundary Bay. These areas constitute the largest wintering grounds for ducks along the British Columbia coast, and the Canadian Wildlife Service have made aerial surveys o f ducks there for a decade. Food studies on dabbling ducks have been conducted in estuarine marshes o f Sturgeon and Roberts Banks by Burgess (1970), but in 1974, the first author initiated the first comprehensive food study o f diving ducks on the tidal flats. An attempt is made here to present the population and food data as a stepping stone for further ornithological investigations as well as for environmental assessment.