“The Regent Of Australia” in the July 2008 issue of BIRD TALK magazine introduced you to the regent parrot, popularly known as the rock pebbler.
In southeastern Australia, regent parrots are patchily distributed from far southwestern New South Wales and northwestern Victoria to neighboring southeastern South Australia. The very restricted range is centered on mid to lower reaches of the Murray River, to the west of the range of the superb parrot (profiled in the May 2008 issue, “Superb Parrot, Superb Country”).
They are more widespread in southwestern Australia, being absent only from the forested southwestern corner, while to the north they reach the Lake Moore district, some 205 miles from Perth, and easternmost records are from western margins of the Nullarbor Plain.
There are notable differences in habitat preferences of regent parrots in southeastern and southwestern Australia, and these differences are reflected in the status of each subspecies. In the southeast there is a strong dependence on the near proximity of extensive stands of mallee woodland, which are utilized for foraging, to nesting areas in riverine forests of river red gums (Eucalyptus camaldulensis).
In surveys conducted between mid-August and mid-December 1984, it was found that a close proximity of major nesting areas to reasonably-sized stands of mallee woodland reflected a dependence of the breeding parrots on mallee for food. Outside the breeding season, birds can be encountered in a wider range of habitats, including Callitris-Eucalyptus woodlands and remnant stands of eucalyptus bordering grainfields or cultivation, especially orchards and vineyards. However, they are always in the vicinity of mallee woodlands, which remain the preferred foraging habitat.
In southwestern Australia, regent parrots frequent a wide variety of wooded habitats, including open forest, Acacia scrublands, trees bordering watercourses and dams or surrounding pastures and cereal paddocks. At a study site near Wickepin, approximately 142 miles south-east of Perth, between four and eight pairs were found nesting in an area comprising mainly a stand of salmon gums (Eucalyptus salmonophloia) with some wandoo (E. wandoo) and morrel (E. longicornis), there being little undergrowth but with a groundcover of grasses, rushes and herbs. Also included were trees growing along a roadside, and the entire area appeared to have been grazed irregularly by sheep. In the wheat belt of Western Australia, I have encountered birds in roadside or railway verges, stock or water catchment reserves, remnant stands of eucalyptus in farmlands or along fence lines bordering wheat fields, and in parks, gardens or golf courses in smaller towns.
Eastern Population Decline
The two subspecies appear to have been affected differently by settlement and land clearing for agriculture. In the southeast, during the past 50 years there has been a significant contraction of the breeding range and a steady decline in numbers, the latter prompting wildlife authorities in the ’80s to initiate extensive field surveys in the breeding range. Based on results from these surveys, together with findings from surveys undertaken in southwestern New South Wales in 1997, the total population in southeastern Australia was estimated to be 1,450 birds. Subsequent surveys undertaken in September to October 2001 and again in September to October 2002 saw the estimated population revised upward to approximately 1,600 individuals.
Loss of habitat was identified as the major threat, with both nesting and foraging habitats being affected adversely by agricultural and forestry practices. It had been suggested that actual or potential nesting trees might have been removed during past forestry operations, but the surveys from the 1980s revealed that many apparently suitable stands of river red gums were not being utilized by the parrots. Consequently, it was concluded that any detrimental effects of forestry practices probably were localized and not important regionally.
However, the clearing of adjoining mallee woodlands deprives the parrots of reliable year-round food resources, with replacement cereal crops supplying food only during summer and being insufficiently reliable to support breeding populations. Maintenance of large stands of mallee woodland adjacent to breeding territories in riverine red gums is essential to the long-term survival of regent parrots in southeastern Australia.
Western Population Change
In southwestern Australia, there have been unexplained fluctuations in the status of regent parrots. Increases in abundance and range followed settlement of the wheat belt, where the birds benefited from cereal growing and the provision of watering places. This was in marked contrast to declines caused by agricultural development in southeastern Australia. A widespread abundance of parrots and claims of depredations on grain crops prompted local authorities in parts of Western Australia to declare the species as vermin, and presumably many birds were killed.
There was a steady decline during the 1940s and 1950s throughout much of the wheat belt, with the birds becoming scarce or locally extinct in districts where formerly they were common, while some simultaneous colonization of newly-cleared lands occurred in coastal and sub coastal districts. Mail surveys undertaken in 1970, 1980 and 1990, in shires throughout the agricultural region of southwestern Australia revealed that regent parrots now are locally extinct or declining in 25 per cent of shires where they were once fairly numerous. It was noted that declines may be offset, partially by apparent increases in some sub coastal districts, particularly on the Swan River coastal plain.