Spotted Ground-thrush (Geokichla guttata) | Text

Spotted Ground-thrush Geokichla guttata

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Justification

Justification of Red List category
This species is listed as Vulnerable since it has a small population which is undergoing a continuing decline because of destruction and degradation of its habitat.

Population justification
This species has 5 subspecies; G. g. guttata, with an estimated <300 pairs [Brown 2015]; G. g. fischeri, previously estimated at c.200 pairs (Ndang'ang'a et al. 2005, 2008), but now believed to be close to extinction (C. Jackson in litt. 2021; J. John in litt. 2021); G. g. belcheri, estimated at 30-40 pairs (F. Dowsett-Lemaire, 2020, pers. comm), and G. g. maxis and G. g. lippensi, which are known only from single specimens. The global population may therefore number 660-680 mature individuals. It is estimated that the population now falls in the band of 250-999 mature individuals.

As this species has 5 subspecies, and based on its distribution, it is assumed to have 5-6 subpopulations. The largest subpopulation is believed to be that of G. g. guttata, which based on its distribution in South Africa is believed to function as 1 subpopulation. This subspecies has an estimated <600 mature individuals. The number of mature individuals in the largest subpopulation is therefore placed in the band 251-1,000.

Trend justification
This species's population is inferred to be declining in line with habitat loss and degradation within its range (Timberlake 2017; F. Dowsett-Lemaire 2020 pers. comm.).

During the years 2001-2020, 6.8% of forest cover was lost across this species’s range according to remote sensing date by Global Forest Watch (2021). Assuming that the population declines at a similar rate to forest loss, this equates to a rate of decline of 3.6% over three generations. During the years 2017-2020, 1.68% of forest cover was lost (Global Forest Loss 2021), equating to a loss of 4.3% when projected forward over three generations.

However, there have been additional reports of the complete destruction of forest blocks in some parts of its range, at Mt Mulanje in Malawi and Mt Namuli in Mozambique (Timberlake 2017; F. Dowsett-Lemaire 2020 pers. comm.). Data from the Southern African Bird Atlas Projects suggests a possible range decline of 28% in South Africa between SABAP1 (1987-1992) and SABAP2 (2007-c.2015) (Cooper 2015), equating roughly to a decline of 12% over three generations.

Therefore, the rate of decline may be higher than that suggested by remote sensing data, and the overall rate of population decline is placed in the band 1-19%.

Distribution and population

Geokichla guttata has a wide but discontinuous distribution (Urban et al. 1997), with migratory coastal subspecies in Kenya and Tanzania (Bennun 1985, Bennun and Njoroge 1999) (fischeri; c.200 pairs and probably decreasing in both countries) (Ndang'ang'a et al. 2005, 2008), with breeding sites at Litipo and Rondo Plateau (Holsten et al., 1991), and South Africa (Harebottle 1991 unpublished, Barnes 2000) (guttata; previously thought to be 400-800 pairs and stable in KwaZulu-Natal [Ndang'ang'a et al. 2005], but now <300 pairs [Brown 2015]), a resident subspecies in Malawi (Dowsett-Lemaire and Dowsett 1988)(belcheri; 30-40 pairs and now extinct on Mt Soche as the forest was completely destroyed by illegal logging c.2000) (F.Dowsett-Lemaire, 2020, pers. comm.). Additionally, Lisau Saddle was destroyed in the 1990s and replaced with Eucalyptus plantations, and the larger forest on Thyolo Mountain was destroyed completely c.2000 (Dowsett-Lemaire et al. 2001; Dowsett-Lemaire & Dowsett, 2006). Two subspecies are known from single specimens, in South Sudan (maxis) and Democratic Republic of Congo (DRC) (lippensi) (Ndang'ang'a et al. 2005). G. g. guttata has been recorded in Mozambique (J. Curverwell per Ndang'ang'a et al. 2005, Parker 2005), and fischeri and belcheri are suspected to occur in other parts of this country (Ndang'ang'a et al. 2005, F. Dowsett-Lemaire per Ndang'ang'a et al. 2005). In 2007 it was discovered on Mt Namuli (Ukalini and Manho), where it appears to be very rare (perhaps due to competition with G. gurneyi) and in 2008 song apparently of this species was heard on Mt Mabu, where the species is also reported to occur by local hunters (Dowsett-Lemaire 2010). It also appears rare on Mabu (although G. gurneyi is not known to occur there). The estimates provided for some known populations suggest that the world population numbers less than 2,500 individuals.

Ecology

It occurs in deep shade in a variety of forest types with deep leaf-litter, from dry Cynometra thicket in Arabuko-Sokoke at sea-level (non-breeding birds) to moist evergreen forest at 1,200-1,700 m in Malawi (Dowsett-Lemaire and Dowsett 1988; Dowsett-Lemaire and Dowsett, 2006). The species winters in tall coastal forests, with fischeri preferring coral rag forests, and guttata possibly using coastal dune forest, and this subspecies prefers larger forests for breeding (Harebottle 1994 unpublished, Ndang'ang'a et al. 2005). The species avoids disturbance-prone areas. It forages amongst the lower branches of leafy trees, on rotting logs and on the forest floor by scratching at leaf litter. It feeds on seeds, fruits, insects and their larvae, and land molluscs (Ndang'ang'a et al. 2005). It has a home range of at least 0.14 ha (Bennun 1985) in the non-breeding season, while in the breeding season in South Africa, densities are typically 1 pair/ha, and the defended territory of a breeding pair is 0.5-1 ha when feeding (Chittenden 2005). Clutch-size is 2 for pairs in Malawi (Belcher 1930; Dowsett-Lemaire and Dowsett 2006), and 2-3 in South Africa (Chittenden 2005). Its nest is described as a cup or bowl constructed from vegetation, small twigs and mud, lined with plant material and feathers; the exact composition of materials is dependent on the habitat and thus differs between subspecies (Belcher 1930; Chittenden 2005; Ndang'ang'a et al. 2005). The species does not conceal its nests well, and they tend to be very exposed and easy to find (Chittenden 2003, Ndang'ang'a et al. 2005), leading to a low breeding success rate, with about 85% of nests recorded as failing by one observer in South Africa (Chittenden 2003). Nests may be re-used after a brood has fledged or even after the nest has been depredated, despite the clear indication that it is at risk. This may be a time- and energy-saving strategy (Chittenden 2003). Snakes, raptors and domestic cats are the main nest predators, and contribute to nearly 50% of breeding failures (Ndang'ang'a et al. 2005). Laying has been noted in November in Malawi (Dowsett-Lemaire and Dowsett, 2006) and in September-March in South Africa (Ndang'ang'a et al. 2005, Chittenden 2005). In 2019, this species was found breeding in Natal province by H. Chittenden (F. Dowsett-Lemaire, 2020, pers. comm.)

Threats

In Tanzania, coastal forest patches are under heavy pressure and becoming increasingly fragmented. Pugu Forest is being degraded as a result of charcoal production (N. Burgess in litt. 2007). Wintering habitat in Kenya is also under heavy pressure, particularly the smaller sites (Waiyaki and Bennun 1999). In Malawi, the forest on Thyolo Mountain was completely destroyed c.2000 by illegal farming, and the small patch of forest on the adjacent Satemwa Tea Estate was cut down by the estate. The forest on Lisau Saddle had been destroyed by the 1990s by the Forestry Department, and the forest patch on Mount Soche was destroyed by illegal loggers shortly after the year 2000 (Dowsett-Lemaire et al. 2001; Dowsett-Lemaire & Dowsett 2006; F. Dowsett-Lemaire 2020 pers. comm.).

At Mt Mulanje (Malawi) a large part of the forest on the southeastern slopes was destroyed by farmers, up to altitudes of 1,500 - 1,600m, but there remains a large block of forest on the upper southeastern slopes, and there is no encroachment into the Ruo Gorge on the southern slopes (F. Dowsett-Lemaire 2020 pers. comm.). At Mount Namuli, Mozambique, most of the forest has been destroyed in recent years (Dowsett-Lemaire 2010; Timberlake 2017). The forest at Mount Mabu is not seriously threatened at present (F. Dowsett-Lemaire, 2020, pers. comm.). In South Africa, mining has destroyed much wintering habitat and may affect more forest in the near future (T. B. Oatley in litt. 1999), while habitat disturbance is increasing in many protected areas (Barnes 2000). The species's recovery is limited by its low breeding success, which is largely due to vulnerability of nests and resultant high rates of predation, perhaps exacerbated by domestic cats where they are present (Chittenden 2003, Ndang'ang'a et al. 2005). This species occasionally suffers mortality from collisions with skyscrapers, probably due to the disorientating effect of city lights during nocturnal migration (Harebottle 1994 unpublished, Oatley 2007). The species may suffer additional habitat loss due to climate change (D. Harebottle in litt. 2016).

Conservation actions

Conservation Actions Underway
CMS Appendix II. In KwaZulu-Natal (South Africa), 22 provincial nature and forest reserves include suitable habitat (Barnes 2000), but funding is being reduced and many are no longer patrolled (T. B. Oatley in litt. 1999). In Malawi, all sites are Forest Reserves, but this confers little protection. In Kenya, a project is aiming to conserve wintering habitat at Arabuko-Sokoke Forest through sustainable use. The forest is also protected by the Forests Act, and the management of several other forests in Kenya is subject to a memorandum of understanding between the Kenya Wildlife Service and Forest Department (Ndang'ang'a et al. 2005). In May 2003, a workshop of international experts, comprising 16 participants from NGOs and governments, was held in Watamu, Kenya (Anon. 2003). During the workshop an International Conservation Action Plan was developed and an International Spotted Ground Thrush Working Group was set up to coordinate the implementation of the plan. Recommended actions included raising awareness, research and monitoring, and effective management of forest habitats (Anon. 2003). Discussions covered the importance of involving local communities and other stakeholders adjacent to the species's sites (T. Mbuvi per Anon. 2003), the use of the species's presence as an indication of high forest quality, and the benefit to local communities of ecotourism associated with the species, which already takes place at some sites (C. Jackson per Anon. 2003; Ndang'ang'a et al. 2005).

Conservation Actions Proposed
Study the species's ecology, including habitat requirements, breeding success, population dynamics, migration routes and survival rates (Ndang'ang'a et al. 2005). Monitor the species's populations (Anon. 2003, Ndang'ang'a et al. 2005). Search for the species in areas where it is suspected to occur, such as northern Mozambique, northern Uganda and northeastern DRC: identify all potential sites and rank their importance (Ndang'ang'a et al. 2005). In Kenya, identify the potential breeding sites at higher altitudes that are likely used by the birds that spend the non-breeding season on the coast (F. Dowsett-Lemaire 2020 pers. comm.). Identify and protect breeding sites and migration "stepping stones" for G. g. fisheri in Tanzania and Mozambique. Further investigate the current status of its forest habitat in South Africa and improve protection of provincial nature and forest reserves (Harebottle 1994 unpublished, T. B. Oatley in litt. 1999). Investigate the current status of the subspecies in Sudan and DRC, when the security situation allows. Study local knowledge of and attitudes towards the species, and raise awareness about it and its threats amongst communities and stakeholders (Anon. 2003; Ndang'ang'a et al. 2005). Implement forest management that favours the species (Anon. 2003), and involve local communities and other stakeholders (T. Mbuvi per Anon. 2003). Provide alternative resources and economic activities for local communities in order to alleviate pressure on forests (Ndang'ang'a et al. 2005). Encourage ecotourism associated with the species (C. Jackson per Anon. 2003). Create an updated Action Plan.

Identification

19-23 cm. Medium-sized, terrestrial thrush of forest. Brownish upperparts. Heavily spotted underparts. Black, vertical stripe down face. Two white wing-bars. Flesh-pink legs. Similar spp. Groundscraper Thrush Psophocichla litsitsirupa larger, more upright, lacks wing-bars, and does not occur in forest. Voice Loud, beautiful song of short, flutey phrases of 4-5 notes. Drawn-out sreee call. Hints At all times difficult to observe, being silent, shy and well-camouflaged, freezing motionless for minutes when disturbed. It feeds on invertebrates, seeds and fruit.

Acknowledgements

Text account compilers
Clark, J.

Contributors
Burgess, N., Dowsett-Lemaire, F., Dyer, M., Ekstrom, J., Evans, M., Harebottle, D., Jackson, C., John, J., Magin, C., Oatley, T.B., Pilgrim, J., Shutes, S., Starkey, M., Symes, A., Taylor, J. & Westrip, J.R.S.

Recommended citation
BirdLife International (2024) Species factsheet: Spotted Ground-thrush Geokichla guttata. Downloaded from https://datazone.birdlife.org/species/factsheet/spotted-ground-thrush-geokichla-guttata on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/12/2024.