Zosterops modestus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PASSERIFORMES	ZOSTEROPIDAE

Scientific Name:

Zosterops modestus

Species Authority:

Newton, 1867

Common Name/s:

English	–	Seychelles Grey White-eye, Seychelles White-eye
French	–	Oiseau-lunettes des Seychelles

Assessment Information [top]

Red List Category & Criteria:

Endangered D ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Taylor, J.

Contributor/s:

Adam, P., Bristol, R., Gerlach, J., Hardcastle, J., Parr, S., Rocamora, G., Shah, N. & Skerrett, A.

Justification:
This species is listed as Endangered because it has an extremely small population. Recent assessments have revealed no evidence of declines in habitat quantity or quality, and following intensive conservation work the population may now number more than 250 mature individuals. Confirmation of this would likely make the species eligible for downlisting.

History:

2008	–	Endangered
2005	–	Endangered
2004	–	Critically Endangered
2000	–	Critically Endangered
1996	–	Critically Endangered
1994	–	Critically Endangered

Geographic Range [top]

Range Description:	Zosterops modestus was thought to survive only in three tiny areas on Mahé, Seychelles and appeared to be declining inexorably towards extinction. In 1996, only 25-35 individuals were known (Rocamora 1997a). In 1997, a previously unknown population was discovered on Conception (Rocamora 1997a). In 1997, this island was estimated to hold "at least 250" individuals (Rocamora and Francois 1999), with c.50 more on Mahé (G. Rocamora in litt. 1999). The population on Conception was estimated at c.275 (244-336) individuals in 1999 and at c.230 (189-266) in 2006, and may be fluctuating or slightly decreasing (R. Bristol in litt. 2004, G. Rocamora in litt. 2007). The population on Mahé was estimated at c.50 birds in 1997 (G. Rocamora in litt. 2007) and at c.60 birds in 2006, and appears to have slightly increased (G. Rocamora in litt. 2007). The transfer of 37 individuals from Conception to Frégate Island in 2001 and 2003 have resulted in the establishment of an estimated population of c.100 individuals there in 2007 (G. Rocamora in litt. 2007), and an estimated total of c.400 individuals in 2007. Further translocations took place in 2007, when 25 birds were transferred to North Island, and 23 to Cousine (Rocamora and Henriette-Payet 2009). Habitat quantity and quality are both increasing (due to rat eradications and restoration programmes in the islands where the species has been transferred) (G. Rocamora in litt. 2007). Results from a monitoring programme started since 1996 indicate a moderate increase in the total population (G. Rocamora in litt. 2007), which was estimated at c.400 birds in 2007 (Rocamora and Henriette-Payet 2009).
Countries:	Native: Seychelles
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The total population is estimated at c.350-450 individuals (R. Bristol in litt. 2004, G. Rocamora in litt. 2007), but the population is conservatively retained in the band 50-249 mature individuals pending evidence that there have been over 250 mature individuals for at least five years.
Population Trend:	Increasing

Habitat and Ecology [top]

Habitat and Ecology:	Data from a recent study have suggested that the populations on Mahé and Conception are genetically isolated from each other (<1-2 migrants per generation), and that one does not represent a subsample of the other (Rocamora and Richardson 2003). They probably became isolated following the decline of the Mahé population, caused by human disturbance, 100-200 years ago, and retain different genetic fragments of the original population. The populations on both Mahé and Conception show low levels of genetic variability, comparable with the inbred island populations of other species (Rocamora and Richardson 2003). The ecology of two populations differs, with those on Conception holding territories in dense mixed woodland with an abundance of native fruiting trees, whereas birds on Mahé show flexibility in habitat choice (Rocamora and Richardson 2003). On Mahé, it is predominantly found in man-made habitats, such as farms, residential areas, orchards, forest edge and mixed secondary forest (Rocamora 1997a), seeming to prefer particular exotic tree and shrub species (Mee 1996a, 1997, Rocamora 1997a). It principally eats insects, but also berries and nectar (Rocamora 1997b). On Mahé, its productivity in the 1990s was poor and recruitment very low, and it is possible that more widely dispersed populations have been lost in the past as productivity has declined (Mee 1997, Rocamora 1997a). It is a cooperative breeder, and on Conception breeding groups and clutch sizes tend to be bigger than on Mahé, with adult birds on Conception also showing low fidelity to particular nests. The trapping of birds has indicated a possible deficit of females on both Mahé and Conception, although the tape luring methods used are more likely to attract males (Rocamora and Richardson 2003).
Systems:	Terrestrial

Habitat and Ecology:

Data from a recent study have suggested that the populations on Mahé and Conception are genetically isolated from each other (<1-2 migrants per generation), and that one does not represent a subsample of the other (Rocamora and Richardson 2003). They probably became isolated following the decline of the Mahé population, caused by human disturbance, 100-200 years ago, and retain different genetic fragments of the original population. The populations on both Mahé and Conception show low levels of genetic variability, comparable with the inbred island populations of other species (Rocamora and Richardson 2003). The ecology of two populations differs, with those on Conception holding territories in dense mixed woodland with an abundance of native fruiting trees, whereas birds on Mahé show flexibility in habitat choice (Rocamora and Richardson 2003). On Mahé, it is predominantly found in man-made habitats, such as farms, residential areas, orchards, forest edge and mixed secondary forest (Rocamora 1997a), seeming to prefer particular exotic tree and shrub species (Mee 1996a, 1997, Rocamora 1997a). It principally eats insects, but also berries and nectar (Rocamora 1997b). On Mahé, its productivity in the 1990s was poor and recruitment very low, and it is possible that more widely dispersed populations have been lost in the past as productivity has declined (Mee 1997, Rocamora 1997a). It is a cooperative breeder, and on Conception breeding groups and clutch sizes tend to be bigger than on Mahé, with adult birds on Conception also showing low fidelity to particular nests. The trapping of birds has indicated a possible deficit of females on both Mahé and Conception, although the tape luring methods used are more likely to attract males (Rocamora and Richardson 2003).

Systems:

Terrestrial

Threats [top]

Major Threat(s):	Loss of native vegetation - particularly large trees - may have been a factor in its decline (Gerlach 1996). However, there is no recent evidence of a significant decline in habitat quantity or quality (R. Bristol in litt. 2004), although invasion by alien plants continues on Mahé (J. Gerlach in litt. 2012). Nest-predation, by the introduced black rat Rattus rattus and Common Myna Acridotheres tristis, is the biggest threat on Mahé (Rocamora 1997a, Rocamora et al. 1999), while fire or disease are the main threats on Conception (Rocamora 1997a, Rocamora 1997b, G. Rocamora in litt. 2007). Conception was inhabited by R. norvegicus but an eradication operation was conducted in August 2007 (G. Rocamora in litt. 2007). On Mahé, abundant Seychelles Bulbul Hypsipetes crassirostris predates nests (Rocamora 1997a, 1997b, Rocamora and Francois 1999). Given its extremely small and fragmented range, the species is vulnerable to sudden stochastic events. Health screening done during 2007 transfers revealed the presence of a widespread Microfileria in the Conception population, although presence of such blood parasites in white-eye populations is common and normally not considered a significant threat (G. Rocamora in litt. 2007).

Major Threat(s):

Loss of native vegetation - particularly large trees - may have been a factor in its decline (Gerlach 1996). However, there is no recent evidence of a significant decline in habitat quantity or quality (R. Bristol in litt. 2004), although invasion by alien plants continues on Mahé (J. Gerlach in litt. 2012). Nest-predation, by the introduced black rat Rattus rattus and Common Myna Acridotheres tristis, is the biggest threat on Mahé (Rocamora 1997a, Rocamora et al. 1999), while fire or disease are the main threats on Conception (Rocamora 1997a, Rocamora 1997b, G. Rocamora in litt. 2007). Conception was inhabited by R. norvegicus but an eradication operation was conducted in August 2007 (G. Rocamora in litt. 2007). On Mahé, abundant Seychelles Bulbul Hypsipetes crassirostris predates nests (Rocamora 1997a, 1997b, Rocamora and Francois 1999). Given its extremely small and fragmented range, the species is vulnerable to sudden stochastic events. Health screening done during 2007 transfers revealed the presence of a widespread Microfileria in the Conception population, although presence of such blood parasites in white-eye populations is common and normally not considered a significant threat (G. Rocamora in litt. 2007).

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway None of the species's current sites on Mahé lie within the Morne Seychellois National Park (Mellanby et al. 1996). Intensive monitoring and research, is still underway mainly on Frégate, North & Cousine that host transferred populations (G. Rocamora in litt. 2007). In July 2000, the Ministere de l'Environnement started 'cat and rat' eradication on several islands including Frégate; subsequently 31 individuals were transferred to Frégate (Rocamora et al. 2002), an island which models suggest could support a population of more than 500 individuals (Rocamora et al. 2002). Almost all of the translocated birds have been regularly resighted, and by 2007 there were c.100 birds on the island. Breeding on Frégate extended beyond the normal breeding season indicating favourable conditions on the island. In 2007, 25 individuals were transferred from Conception to North Island, following successful rat eradication in 2005, whilst 20 were transferred from Conception and three from Mahé to Cousine (G. Rocamora in litt. 2007). Intensive habitat restoration has been carried out on North Island and Cousine, with the species attempting to breed there in November 2007 (G. Rocamora in litt. 2007). Predator control and nest monitoring have been conducted on Mahé since 2006, and population monitoring is being carried out on the five islands where the species now occurs (G. Rocamora in litt. 2007). Conservation Actions Proposed Continue to monitor population trends in all islands occupied by the species (both source and transferred populations). Create a protected area, and manage the habitat (Rocamora 1997a) to preserve the key population on Conception (Rocamora 1997a, N. J. Shah and S. Parr in litt. 1999). Encourage preservation of large garden trees in residential areas where the species is present on Mahé to help their short-term survival there (Gerlach 1996, Rocamora 1997a). Continue rat control and protection of nests in the two main Mahé subpopulations (G. Rocamora in litt. 2007). Consider translocation to other suitable predator and competitor-free islands (Gerlach 1996, Rocamora 1997a, N. J. Shah and S. Parr in litt. 1999, A. Skerrett in litt. 1999). Continue to mix individuals from different source populations during translocations, thus recombining genetic variation in the species (Rocamora and Richardson 2003).

Conservation Actions:

Conservation Actions Underway
None of the species's current sites on Mahé lie within the Morne Seychellois National Park (Mellanby et al. 1996). Intensive monitoring and research, is still underway mainly on Frégate, North & Cousine that host transferred populations (G. Rocamora in litt. 2007). In July 2000, the Ministere de l'Environnement started 'cat and rat' eradication on several islands including Frégate; subsequently 31 individuals were transferred to Frégate (Rocamora et al. 2002), an island which models suggest could support a population of more than 500 individuals (Rocamora et al. 2002). Almost all of the translocated birds have been regularly resighted, and by 2007 there were c.100 birds on the island. Breeding on Frégate extended beyond the normal breeding season indicating favourable conditions on the island. In 2007, 25 individuals were transferred from Conception to North Island, following successful rat eradication in 2005, whilst 20 were transferred from Conception and three from Mahé to Cousine (G. Rocamora in litt. 2007). Intensive habitat restoration has been carried out on North Island and Cousine, with the species attempting to breed there in November 2007 (G. Rocamora in litt. 2007). Predator control and nest monitoring have been conducted on Mahé since 2006, and population monitoring is being carried out on the five islands where the species now occurs (G. Rocamora in litt. 2007).

Conservation Actions Proposed
Continue to monitor population trends in all islands occupied by the species (both source and transferred populations). Create a protected area, and manage the habitat (Rocamora 1997a) to preserve the key population on Conception (Rocamora 1997a, N. J. Shah and S. Parr in litt. 1999). Encourage preservation of large garden trees in residential areas where the species is present on Mahé to help their short-term survival there (Gerlach 1996, Rocamora 1997a). Continue rat control and protection of nests in the two main Mahé subpopulations (G. Rocamora in litt. 2007). Consider translocation to other suitable predator and competitor-free islands (Gerlach 1996, Rocamora 1997a, N. J. Shah and S. Parr in litt. 1999, A. Skerrett in litt. 1999). Continue to mix individuals from different source populations during translocations, thus recombining genetic variation in the species (Rocamora and Richardson 2003).

Citation:	BirdLife International 2012. Zosterops modestus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.
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