2 research outputs found
Nest temperature fluctuations in a cavity nester, the southern ground-hornbill
Southern ground-hornbills Bucorvus leadbeateri inhabit savanna and bushveld regions of
South Africa. They nest in the austral summer, which coincides with the wet season and
hottest daytime temperatures in the region. They are secondary cavity nesters and typically
nest in large cavities in trees, cliffs and earth banks, but readily use artificial nest boxes.
Southern ground-hornbills are listed as Endangered in South Africa, with reintroductions
into suitable areas highlighted as a viable conservation intervention for the species. Nest
microclimate, and the possible implications this may have for the breeding biology of
southern ground-hornbills, have never been investigated. We used temperature dataloggers
to record nest cavity temperature and ambient temperature for one artificial and 11 natural
southern ground-hornbill tree cavity nests combined, spanning two breeding seasons. Mean
hourly nest temperature, as well as mean minimum and mean maximum nest temperature,
differed significantly between southern ground-hornbill nests in both breeding seasons.
Mean nest temperature also differed significantly from mean ambient temperature for both
seasons. Natural nest cavities provided a buffer against the ambient temperature
fluctuations. The artificial nest provided little insulation against temperature extremes,
being warmer and cooler than the maximum and minimum local ambient temperatures,
respectively. Nest cavity temperature was not found to have an influence on the breeding
success of the southern ground-hornbill groups investigated in this study. These results have
potentially important implications for southern ground-hornbill conservation and artificial nest design, as they suggest that the birds can tolerate greater nest cavity temperature
extremes than previously thought.The Ford Wildlife Foundation and the First Rand Foundation (Project reference : 033391).http://www.elsevier.com/locate/jtherbio2018-05-31hb2017Veterinary Tropical Disease
Habitat structure and diversity influence the nesting success of an endangered large cavity-nesting bird, the Southern Ground-hornbill
Habitat features can have a profound effect on the nesting success of birds. Savannas are often
managed with predators and large herbivores as priority species, with little thought to the
many bird species that management decisions could affect. Using a data set spanning seven
breeding seasons, we examined how nesting success of Southern Ground-hornbills (SGHs)
Bucorvus leadbeateri in the Kruger National Park varied as a result of various environmental
and habitat factors within a radius of 3 km surrounding the nest site. Identifying which factors
affect nesting success will allow for targeted management efforts to ensure the long-term
survival of SGHs both within and outside of protected areas. Habitat structure and diversity
of the vegetation surrounding the nest were the most influential factors on SGH nesting
success. SGHs require open grassy areas for foraging and areas with large trees for nesting.
Savanna habitat drivers such as elephants and fire should be managed to ensure that sufficient
large trees are able to establish in the landscape and to control for bush encroachment. This is
especially important in areas earmarked for SGH reintroductions. Nest sites of SGHs should
be monitored to mitigate any structural changes in the habitat surrounding the nests. Nests
should be modified or artificial nest sites provided, where nests have been damaged or lost, to
ensure the continued presence of these birds in African savannas.
CONSERVATION IMPLICATIONS : Habitat structure and diversity surrounding Southern Groundhornbill
nests has a significant impact on their nesting success. This highlights the importance
of monitoring vegetation change in savanna habitats where they occur. Management of
savanna areas should take factors that influence bush encroachment, such as fire and elephants,
into account to ensure the long-term persistence of these birds.The Ford Wildlife Foundation and the First Rand
Foundation.http://www.koedoe.co.zaam2018Veterinary Tropical Disease