White-fronted chat (Epthianura albifrons) population in the Sydney Metropolitan Catchment Management Authority area - endangered population listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list a population of the White-fronted Chat Epthianura albifrons (Jardine & Selby, 1828) in the Sydney Metropolitan Catchment Management Authority area as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act. Listing of Endangered populations is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The White-fronted Chat Epthianura albifrons (Jardine & Selby, 1828) (family Meliphagidae) is not currently listed as an Endangered species in Part 1 of Schedule 1 or a Critically Endangered species in Part 1 of Schedule 1A of the Act and as a consequence populations of this species are eligible to be listed as Endangered populations.
2. The White-fronted Chat Epthianura albifrons is an endemic Australian passerine bird, measuring 12 cm in length and weighing approximately 13 g. It has a short slender bill, long spindly legs, a short square-tipped tail and rounded wings (Higgins et al. 2001). Classified as a honeyeater it is most similar in form to its close relatives, the Orange E. aurifrons, Yellow E. crocea and Crimson E. tricolor Chats from which it is easily distinguished by its black and white colouration. The plumage of the male is more striking than that of the female with the juvenile plumage being most similar to the female. The voice is a distinctive 'tang, tang' used as a contact call (Higgins et al. 2001).
3. The distribution of the White-fronted Chat extends across the southern half of Australia, from the southernmost areas of Queensland to southern Tasmania and across to Western Australia as far north as Carnarvon (Barrett et al. 2003). Found mostly in temperate to arid climates and very rarely seen in sub-tropical areas, the White-fronted Chat occupies foothills and lowlands below 1000 m above sea level (North 1904; Higgins et al. 2001; Barrett et al. 2003). In New South Wales the White-fronted Chat occurs mostly in the southern half of the state, occurring in damp open habitats along the coast, and near waterways in the western part of the state (Higgins et al. 2001). Along the coastline, White-fronted Chats are found predominantly in saltmarsh vegetation although they are also observed in open grasslands and sometimes in low shrubs bordering wetland areas. (North 1904; Higgins et al. 2001; Barrett et al. 2003).
4. Two isolated sub-populations of White-fronted Chats are currently known from the Sydney Metropolitan Catchment Management Authority area (accessed 8 July 2009); one at Newington Nature Reserve on the Parramatta River and one at Towra Point Nature Reserve in Botany Bay. These sub-populations are separated from each other by 25 km of urbanised land, across which White-fronted Chats are unlikely to fly. They are isolated by even greater distances from the nearest extant populations outside the Sydney Metropolitan Catchment Management Authority area, at Ash Island north of Newcastle and Lake Illawarra, south of Wollongong. The last records of White-fronted Chats at Penrith Lakes (2001), Hawkesbury Swamps (2002), Tuggerah Lake (1997) and Lake Macquarie (1998) have not been repeated in recent years (Alan Morris, pers comm. 2009).
5. Newington Nature Reserve is located on the Parramatta River and is approximately 50 ha in size including 14 ha of saltmarsh surrounded by mangroves (Saintilan and Rogers 2008). White-fronted Chats are regularly observed in the saltmarsh with occasional sightings reported from other parts of Sydney Olympic Park and in grassland on the bank of the northern side of the Parramatta River (Oxenham pers. comm. 2008). Banding and resighting of individual birds in 2009 indicates that these birds are from the same subpopulation (R. Major and K. Oxenham, unpubl. data). White-fronted Chats were once found in saltmarsh adjoining the "Waterbird Refuge" at Bicentennial Park, a wetland close to Newington Nature Reserve, but no sightings have been recorded at this location since 1997. Intensive colour-banding and survey efforts indicate that the population in April 2009 consisted of 8 individuals (R. Major and K. Oxenham, unpubl. data).
6. Towra Point Nature Reserve is located on the southern side of Botany Bay and is approximately 385 ha in size, including approximately 157 ha of saltmarsh (accessed 8 July 2009). White-fronted Chats are regularly observed in the saltmarsh and on the sandy shoreline of a small island. Historically White-fronted Chats have been recorded in other locations on the Kurnell Peninsular but there have been no records in recent years from beyond the nature reserve. The minimum number of birds at Towra Point is 19 (Jenner 2008) with a plausible maximum of 50.
7. The White-fronted Chat is regarded as resident in many areas, but has been referred to as nomadic in some places (Higgins et al. 2001). There is no evidence of any migratory movements although flocks of White-fronted Chats have been recorded gathering temporarily in some areas in response to temporary high abundance of food. A mark-recapture study of White-fronted Chats near Melbourne reported 189 recaptures all within 5 km of the banding site (Higgins et al. 2001). Other White-fronted Chats banded in Western Australia, were all recaptured within 2 km of the banding site (ABBBS 2008). Banding studies between June 2008 and April 2009 at Newington Nature Reserve indicated that there was no immigration or dispersal of birds. The species is sensitive to human disturbance and is not found in built areas (Jenner 2008). Collectively this information indicates that the two subpopulations are disjunct, both from each other and from the nearest populations outside the Sydney Metropolitan Catchment Management Authority area.
8. White-fronted Chats are gregarious, although they do not form mixed species flocks (Higgins et al. 2001). They are usually found foraging on bare or grassy ground in wetland areas, occurring singly and in pairs, and frequently forming small flocks of up to 50 birds particularly in the non-breeding season in autumn and winter (Major 1991a). During the breeding season they form simple monogamous pairs, but will join small flocks to feed and roost. They are insectivorous, with flies and beetles being the major components of their diet, feeding from the ground or catching flying insects close to the ground (Major 1991a).
9. The breeding biology of the White-fronted Chat has not been investigated extensively in New South Wales, but is well known in Victoria (Major 1991b) and Western Australia (Williams 1979). White-fronted Chats have been observed breeding from late July through to early March. Nests are built in low vegetation, particularly Sclerostegia arbuscula, Suaeda australis, and Sarcocornia quinqueflora (Major 1991b; Straw 1999). In the Sydney region nests have also been observed in low isolated mangroves (K.Oxenham, pers. comm. 2007; R. Major pers. comm. 2008). Nests are open-cup structures with irregularly formed exteriors of coarse dried grasses or plant stalks, neatly lined with fine dried grass, thin fibrous roots and animal hair (Major 1991b; Higgins et al. 2001). Mean nest height is 23 cm above the ground (Major 1991b) with occasional nests found at up to 2.5 m above the ground (North 1904). The clutch size is usually 2 or 3 eggs, averaging 2.75 eggs. The complete nesting cycle from nest-building to independent young is approximately 50 days and a second clutch can be started immediately after the first clutch has reached independence (Major 1991b). Individually-marked White-fronted Chats have been observed to re-nest up to five times in a season after previous clutches have been unsuccessful. The life span of White-fronted Chats in the wild is unknown but estimated at approximately five years (Major pers. comm. 2008). Birds can breed at one year of age. The generation time, based on the age of maturity and life span is calculated as three years, the same as that estimated for the conspecific Yellow Chat (Garnett & Crowley 2000).
10. White-fronted Chats have been recorded from 55 different localities in the Sydney region dating back to the pre-1900s (Jenner 2008). Birds had disappeared from over half of these localities by the end of the 1960s with only the Towra Point and Newington sub-populations remaining after 2002. From these data it appears that there has been a large reduction in geographic range.
11. The population of White-fronted Chats at Newington Nature Reserve has undergone considerable decline over the past 10 years, a time frame consistent with that recommended by IUCN (2008) for estimating population change. Flocks of up to 26 birds were recorded in 1997 (Straw 1999; Eckert 2000) and up to 22 birds in 2000 although the maximum flock size recorded in 2001 was 10 birds (Jenner 2008). A flock of 20 birds was recorded in 2003 but since then no flock larger than 11 has been recorded. In 2007 flocks of 11 birds were recorded on numerous occasions and in 2008 six males and two females were captured and banded, with one female remaining unbanded. Follow-up surveys in 2008 failed to detect any additional birds, indicating a total population of nine birds. One banded female was later found dead due to predation on the nest, reducing the population to eight. There was no recruitment during the breeding season of 2008, with two observed nests lost to predators (Jenner 2008).
12. Little quantitative data are available on population trends of White-fronted Chats at Towra Point Nature Reserve. Anecdotal observations suggest that the number of birds has declined since the 1970s (E O'Brien, in litt). "Viable" populations have been reported (Hoskin et al 1991; Keast 1995) but no numerical data are available. A biodiversity survey in 2006 reported up to 16 birds (Schulz 2006) and systematic counts in 2008 regularly recorded between 14 and 19 individuals (Jenner 2008). Given that the area of saltmarsh at Towra Point is much larger than that at Newington, it is possible that some birds were not detected, but it is unlikely that a large population remains. The absence of recent records from other parts of the Kurnell peninsular suggests that this sub-population has declined.
13. The major threats to White-fronted Chats in the Sydney Metropolitan Catchment Management Authority area are reduction in habitat size and quality, human disturbance (Jenner 2008) and elevated nest-predation levels (Major 1991b). Mangrove encroachment (Saintilan et al. 2009) and sea-level rise associated with global warming (Hughes 2003) present an additional future threat to their saltmarsh habitat. Saltmarsh at Newington Nature Reserve has historically been affected by inappropriate hydrological regimes and mangrove incursion (Straw 1999), but in recent years the area of saltmarsh in the reserve has increased and its condition has improved as a result of the reintroduction of tidal flushing and an active program of mangrove seedling removal (Oxenham pers comm. 2008). Urbanisation has isolated populations in small saltmarsh remnants, leaving populations vulnerable to stochastic threats associated with small population size. Because they nest close to the ground, White-fronted Chat nests are prone to predation from snakes and mammals, particularly Feral Cats Felis catus, European Red Foxes Vulpes vulpes, and rodents (Major 1991b), as well as birds, particularly ravens Corvus spp. The abundance of many of these predators is higher in areas near human settlement. 'Predation by the European Red Fox Vulpes vulpes (Linnaeus, 1758)', 'Predation by the Feral Cat Felis catus (Linnaeus, 1758)', 'Anthropogenic climate change', are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995. 'Coastal Saltmarsh in the NSW North Coast, Sydney Basin and South East Corner Bioregions', is listed as an Endangered Ecological Community under the Threatened Species Conservation Act 1995.
14. The population of the White-fronted Chat Epthianura albifrons (Jardine & Selby, 1828) in the Sydney Metropolitan Catchment Management Authority area is eligible to be listed as an Endangered population as, in the opinion of the Scientific Committee it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:
Clause 19
It satisfies the following paragraph and also meets the criteria specified in the following clauses:
(a) it is disjunct or near the limit of its geographic range.
Clause 20
The size of the population has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon, a large reduction based on:
(a) an index of abundance appropriate to the taxon
(b) geographic distribution, habitat quality or diversity, or genetic diversity.
Clause 21
The geographic distribution of the population is estimated or inferred to be highly restricted and:
(a) projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(b) the following conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of locations.
Clause 22
The estimated total number of mature individuals in the population is low and either:
(a) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(b) the following conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of locations.
Clause 23
The estimated total number of mature individuals of the population is observed,
estimated or inferred to be very low.
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 23/04/10
Exhibition period: 23/04/10 - 18/06/10
References:
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