Parrots of the Sydney Region: Population Changes Over 100 Years
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Parrots of the Sydney region: population changes over 100 years Shelley Burgin and Tony Saunders 1College of Health and Science, University of Western Sydney, Locked Bag 1797, South Penrith Distribution Centre 1797 Email: [email protected]; [email protected] With European settlement, the landscape of Australia changed dramatically due to clearing for agriculture, forestry and urban development. These changes have impacted on the diversity and abundance of many Australian native fauna. The avifauna provides a conspicuous example. Despite their generally striking colours, strident call and large body size, the status of parrot populations in urban regions have been largely ignored. We reviewed three bird data bases to determine trends. The two species, recorded within 10 km of Sydney’s General Post Office pre-1900, are no longer present, although 15 species are now known from this area. Populations of the five most common of these species have continued to increase in the last 20 years, one appears to have remained unchanged and others are present in insufficient numbers to comment. No species appears to have declined in numbers. Escapees or deliberate releases from aviaries are major sources of birds that establish ABSTRACT viable populations, although even in these populations, numbers may also have been supplemented by vagrants. We suggest that supplementary feeding, and changes in the vegetation in the city landscape, are major contributing factors to the current diversity and abundance of parrots within Sydney. Key words: range extension, urban wildlife, feral birds, urban birds, aviary escapees. Introduction With European settlement of Australia, extensive The avifauna provides a conspicuous example of a taxon clearing occurred for agriculture, forestry, and urban that continues to be affected by urbanisation (Parsons and development. The associated landscape changes have Major 2004), and a large number of bird communities impacted on the local wildlife in ways different to those (e.g. Tomialojc and Profus 1977, Suhonen and Jokimaki imposed by Aboriginal management (Burgin 2004). The 1988, Catterall et al. 1991, Ferrier et al. 1993, Sewell and outcome has been the widespread removal of endemic Catterall 1998, Catterall 2004, Parsons and Major 2004, vegetation, and associated wildlife habitat fragmentation. Recher 2004), and individual species (eg. Buchanan 1989; Subsequently, there have been altered patterns of Low 1994; Major et al. 1996, Parsons and Major 2004) wildlife usage and ecosystem dynamics (eg. changes in have been studied within urban boundaries. However, wildlife abundance and species composition, vegetation while the dynamics of a range of the larger bird species structure, floristic composition); together with the have been investigated (eg. ibis - Ross 2000, 2004, Perry introduction of feral animals and their parasites; more 2001; gulls – Smith and Carlile 1993, Belant 1997, Temby effective hunting regimes (i.e. guns instead of spears) 2004; currawongs – Buchanan 1989, Major et al. 1996), that have resulted in additional species being targeted; despite their often striking colours, strident call, and large and changed grazing regimes (Recher et al. 1993). size, parrots have attracted less attention. These post-European changes have culminated in a The catalyst for reviewing the changes in residency of highly urbanised country, with most of the population parrots in the Sydney region over the past 100 years clustered between the Great Diving Range and the resulted from a chance discussion with Dr Richard Major eastern seaboard. With an area of approximately 3,000 (Australian Museum). He commented that only two km2, the Sydney region is one such location (White and parrot species had been recorded within 10 kilometres of Burgin 2004). With the development of the urban/peri- the Sydney’s General Post Office (GPO) prior to 1900: urban landscape, a mosaic of new habitat types have the turquoise parrot Neophema pulchella and the ground been continuously formed and reformed. Within this parrot Pezoporus wallicus. highly modified and dynamic landscape, there have The turquoise parrot is now classified as a ‘vulnerable’ been species that have benefited with resulting increased species on Schedule 2 of the NSW Threatened Species abundance, others have declined and some species have Conservation Act 1995 (http://www.nationalparks.nsw. become locally extinct. There have also been species gov.au/npws.nsf/content/turquoise+parrot+vulnerable whose abundance has apparently been unaffected +species+listing), and no longer occurs within this 10 (Catterall 2004). kilometre radius. The nearest contemporary sightings to Burgin and Saunders Sydney’s core urban area are in the Wisemans Ferry and Table 1. Parrots sighted within 10 km of Sydney General North Richmond areas, both in excess of 50 km from Post Office since 2000 (Source: Cumberland Bird central Sydney. The nearest confirmed sighting of ground Observers Club records). parrots is at Barren Grounds, near Robertson in southern Common name Scientific name New South Wales, considerably further from Sydney’s centre than the sightings of the turquoise parrot. These Yellow-tailed black-cockatoo Calyptorhynchus funereus two endemic species are, therefore, now locally extinct Galah Cacatua roseicapilla within the city centre, although the turquoise parrot Long-billed corella Cacatua tenuirostris is still present in peri-urban Sydney (Cumberland Bird Little corella Cacatua sanguinea Observers’ Club Database, accessed October 2005). Based on this revelation, we decided to investigate the current Sulphur-crested cockatoo Cacatua galerita trends in parrot populations in the Sydney region. Cockatiel Nymphicus hollandicus Rainbow lorikeet Trichoglossus haematodus Methods Scaly-breasted lorikeet Trichoglossus chlorolepidotus To determine the current species diversity and abundance Musk lorikeet Glossopsitta concinna of parrots in Sydney, information was sought from Australian king-Parrot Alisterus scapularis three organisations: Birds Australia (http://www.birds Crimson rosella Platycercus elegans australia.com.au/), Cumberland Bird Observers’ Club (http://www.cboc.org.au/wattlebird.html), and Field Eastern rosella Platycercus eximius Ornithologists Club – Birding New South Wales (http: Swift parrot Lathamus discolor //www.birdingnsw.org.au/). Red-rumped parrot Psephotus haematonotus Birds Australia conducted two nation-wide atlas Orange-bellied parrot Neophema chrysogaster surveys, one between 1977-1981 (Blakers et al. 1984), and another across 1998-2001 (Barrett et al. 2003). those that are not local endemics (eg. galah Cacatua The bird species encountered during the survey period roseicapilla, long-billed corella Cacatua tenuirostris, and were checked off on a list by volunteers. There was little corella Cacatua sanguinea; Table 2). Other species no measure of abundance made. Barrett and Silcocks (eg. orange-bellied parrot Neophema chrysogaster, swift (2002) adjusted the results of the two census datasets parrot Lathamus discolor) were infrequently sighted and and used probability of encounter with a species as the were probably vagrants. basis of comparison between the two datasets. The status of the more common species that were The Field Ornithologists Club - Birding New South Wales surveyed between 1977-1981 and 1998-2001 are has undertaken regular bird counts that encompass the presented in Figure 1. These data indicated that five of Greater Sydney area, for over 20 years. These counts the seven species presented in Table 1 have increased in have been taken in an area that extends north to Wyong probability of being recorded over time, while only one on the central coast of New South Wales, west to Leura (crimson rosella Platycercus elegans) that was commonly in the Blue Mountains, and as far south as Shellharbour encountered in the earlier survey, has maintained its in the south. In the Sydney area, the counts were based numbers. Budgerigar Melopsittacus undulatus numbers on 10 regions, and a team of 10 volunteers sampled each were low in both surveys. of these regions for two days each year. Species observed were recorded and individual birds were counted during Annual survey data collected between 1978 and 1987 these surveys. (Figure 2) indicated that, as would be expected, species abundance has tended to fluctuate. However, there was a Cumberland Bird Observers’ Club has maintained a sustained rise in the abundance of parrots between 1978 database since 1986 that members contribute to on an and 1983. Between 1983 and 1987 the numbers were on-going basis. Volunteers are asked to qualitatively maintained at lower levels than observed between 1982 record the maximum number of birds within a survey (5- 10, 6-20, 21-50, 51-100, >100), for each species that they and 1984, although they were substantially higher than encountered. Along with this information, behavioural in earlier survey years. The flock size data obtained in traits (e.g. habitat, stage of breeding) are noted. another survey for two of the species presented in Figure 2 (sulphur-crested cockatoo Cacatua galerita and rainbow Information obtained from the databases was current in lorikeet Trichoglossus haematodus) indicate that flock sizes October 2005. In addition, information was also gleaned have increased. There were more flocks with >20 and from the literature to complement the data obtained from >50 birds in 2005 than in 1986 (Figure 3). the databases. Discussion Results Between 2000 and 2005,