Title:

The biology and management of the regionally threatened Damara tern (Sterna balaenarum) at Struisbaai, South Africa

Author(s):
Publication Year:
1996
Abstract:

The breeding success of the damara tern Sterna balaenarum, between Struisbaai and Arniston, on the South African south coast, was monitored on"a daily basis during thefive month breeding period (October 1995-February 1996). The breeding population was estimated at between 18-22 birds, which is approximately the same as was estimated 16 years ago. Breeding took place six kilometres west of th~ De Mond Nature Reserve. No breeding took place at the previously reported sites within or east ofthe De Mond Nature Reserve. Breeding success was extremely low (15.3 %), with only three chicks fledging from a total of 17 nests. It was recorded, for the first time, that pairs could lay up to two replacement clutches after earlier clutch failure. Breeding failure was caused by rain, sand inundation of eggs, eggs and. chicks being crushed by vehicles, disappearance of chicks, possible disturbance by the observer and an unknown cause. Birds were seen foraging in the Heuningnes Estuary, within the surf zone along the coast and out at sea. Foraging for the provisioning of chicks appeared to occur predominantly in the surf zone and further out to sea. Observation ofthe hourly provisioning rates showed a daily increase in the quantity offish being eaten by the chick until the chick was eight days old, after which it remained fairly constant. No chick mortality could be attributed to starvation. If the damara tern population is to persist in the area, it is recommended that the inter-dune slacks and dune system b~ closed to vehicles and pedestrians; that beach users be educated by means of signboards and television programmes (eg. 50/50), that marram grass Ammophilia arenaria be removed from the frontal dune systems and inter-dune slacks, and that further research be conducted on the Struisbaai damara tern population. Keywords: Damara tern, breeding success, disturbance, foraging, provisiorung, management, Struisbaai.

Place:
Cape Town, South Africa
Publisher:
Fitzpatrick Institute, University of Cape Town
Type:
MSc Thesis
Item Type:
Thesis
Language:
en