The Nesting Success of Taita Thrush Turdus helleri in Afrotropical Fragments, Kenya
DOI:
https://doi.org/10.2200/aerj.v3i1.200Keywords:
Nesting Success, Taita Thrush Turdus Helleriin, Afrotropical Forest FragmentsAbstract
Nesting behavior and nest success are key components for assessing the conservation status of avian species. This study focused on the critically endangered Taita Thrush (Turdus helleri), endemic to the Taita Hills of southern Kenya. We surveyed all the four remnant forests fragments (Chawia, Yale, Mbololo and Ngangao) where the species survives. Taita thrush nests were placed on well branched trees with at least a climber at an average height of 4.3 m (range 2 m -7 m, N = 38) above the ground. Based on the data from the thirty eight nests found, on average, 34% of all the nests initiated survived to produce fledglings across all the four fragments. Success rates appeared to differ across forest fragments. Daily survival probability was estimated in all the four fragments and later narrowed down to two large fragments that had more than one nest. Daily survival probability for all four fragments was estimated at 0.93 ± 0.03 with a daily survival rate for egg incubation and nestling periods of 0.11. Daily survival probability for Ngangao and Mbololo was estimated at 0.88 ± 0.08 and 0.95 ± 0.06 respectively with a daily survival rate for egg incubation and nestling period(s) of 0.2 and 0.21 respectively. Continuous nest monitoring revealed that nest predation accounted 55.3% (unknown animal predators 76.19% and known animal predation 23.81%), abandoned nests 10.53% (unknown reasons for nest abandonment) and 34.20% fledged nests. The predators included, a Boomslang (Dispholidus typus) snake, a nocturnal rodent(not clearly identified by camera) and an African goshawk (Accipiter tachiro) for both stages of incubation and nestling development(snake-1 nest, bird of prey -1 nest, rodents- 3 nests and unknown predators- 16 nests). Nest predation was highest in Ngangao but this could have been attributed by the fact that the same fragment had more nests observed than all other fragments. The low nesting success of Turdus helleri suggests that conservation efforts should ensure that Taita forest fragments are properly managed to maintain natural habitat.
References
Beentje, H. J. and Ndiang'ui, N. (1988). An ecological and floristic study of the forests of the Taita Hills, Kenya. UTAFITI, Occas. Pap. Nation. Mus. Kenya, 1(2), 23-66.
BirdLife International (2018). IUCN Red List for birds. Retrieved from http://www.birdlife.org
Borghesio, L., Githiru, M., Wagura, L. and Gichia, J. M. Final report for the proposal: Reassessment of the status of the Critically Endangered Taita thrush A project funded by the African Bird Club.
Brooks, T. M., Mittermeier, R. A., Mittermeier, C. G., Da Fonseca, G. A., Rylands, A. B., Konstant, W. R. and Hilton‐Taylor, C. (2002). Habitat loss and extinction in the hotspots of biodiversity. Conservation biology, 16 (4), 909-923.
Brooks, T., Lens, L., Barnes, J., Barnes, R., Kihuria, J. K. and Wilder, C. (1998). The conservation status of the forest birds of the Taita Hills, Kenya. Bird Conservation International, 8 (2), 119-139.
Callens, T. O. M., Galbusera, P., Matthysen, E., Durand, E. Y., Githiru, M., Huyghe, J. R. and Lens, L. U. C. (2011). Genetic signature of population fragmentation varies with mobility in seven bird species of a fragmented Kenyan cloud forest. Molecular Ecology, 20 (9), 1829-1844.
Cox, W. A., Pruett, M. S., Benson, T. J., Chiavacci, S. J. and Thompson III, F. R. (2012). Development of camera technology for monitoring nests.
Cresswell, W. (1997). Nest predation: the relative effects of nest characteristics, clutch size and parental behaviour. Animal Behaviour, 53 (1), 93-103.
Fahrig, L. (2003). Effects of habitat fragmentation on biodiversity. Annual review of ecology, evolution, and systematics, 34 (1), 487-515.
Githiru, M., and Lens, L. (2004). Using scientific evidence to guide the conservation of a highly fragmented and threatened Afrotropical forest. Oryx, 38 (04), 404-409.
Githiru, M., Lens, L. and Cresswell, W. (2005). Nest predation in a fragmented Afrotropical forest: evidence from natural and artificial nests. Biological conservation, 123 (2), 189-196.
Himberg, N. (2011). Traditionally Protected Forests Role within Transforming Natural Resource Management Regimes in Taita Hills, Kenya.
Martin, T. E. and Geupel, G. R. (1993). Nest-Monitoring Plots: Methods for Locating Nests and Monitoring Success (Métodos para localizar nidos y monitorear el éxito de estos). Journal of field Ornithology, 507-519.
Mayfield, H. (1975). Nesting success calculated from exposure. The Wilson Bulletin, 255-261.
Newmark, W. D., and Stanley, T. R. (2011). Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot. Proceedings of the National Academy of Sciences, 108 (28), 11488-11493.
Skarbek, C. (2009). A review of endemic species in the Eastern Arc Afromontane Region: Importance, inferences, and conservation. Macalester Reviews in Biogeography, 1 (1), 3.
Spanhove, T., Callens, T., Hallmann, C. A., Pellikka, P., and Lens, L. (2014). Nest predation in Afrotropical forest fragments shaped by inverse edge effects, timing of nest initiation and vegetation structure. Journal of Ornithology, 155(2), 411-420.
Spanhove, T., Lehouck, V., Boets, P., Lens, L., (2009). Forest fragmentation relaxes natural nest predation in an Afromontane forest. Animal Conservation 12, 267–275
Wagura, L., Githiru, M., & Borghesio, L. (2012). Notes on the nesting biology of Taita Apalis Apalis fuscigularis. Bulletin of the African Bird Club, 12, 42-46