A preliminary investigation into the status, distribution and some aspects of the foraging ecology of the southern ground hornbill (Bucorvus cafer) in Natal.
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Date
1990
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Abstract
A study on the distribution, status and selected aspects of
the foraging ecology of B. cafer in Natal, was undertaken
from January 1989 to December 1990.
A census was initiated to assess the distribution of B.
cafer in Natal. 436 sightings were reported from 187 locations.
B. cafer occurs throughout Natal, except in the far
northwestern regions. A population estimation based on this
census suggest that between 300-350 B. cafer individuals exist
in Natal, excluding KwaZulu regions. The large area occupied
by KwaZulu and the protection of this species by Zulu
folk law, suggest that the population may be considerably
larger.
Selected aspects of the foraging ecology of the two study
groups in the Natal midlands were examined, focusing on the
role that individuals play in provisioning the nestling,
nest bound female and fledgling.
B. cafer are predominantly carnivorous. They are able to
utilise habitats used for a wide variety of agricultural
practices. The major criteria, in terms of habitat selection,
being a short (0.5 m) or sparse ground cover. Younger
birds were less successful than older individuals at digging
and probing for food. Foraging success rate of the juvenile
increased from 7.2% prior to nesting, to 51.2% during nesting.
The acquisition of foraging skills, particularly digging
and probing, takes time and experience.
Frogs were the major food item fed to the nestling and nest
bound female. The presence of helpers reduced the amount of
feeding by parent birds. Helpers in the stainbank group supp
plied 25% of food bundles to the nest. The juvenile did not
act as a helper. Subadults helped most during the periods
when the demand for food delivery to the nest was highest,
and at the end of the nesting period. Helpers reduced the
amount of time that the dominant female spent away from the
nest during incubation and early nestling phase. Once the
female left the nest, the male reduced his food delivery
rate. An abundance of frogs, close to the nest, enabled a
single pair to adequately provision a nestling. The parent
birds provisioned the fledgling until the following breeding
season.
Description
Thesis (M.Sc.)-University of Natal, 1990.
Keywords
Hornbills., Theses--Zoology.