The distribution and status of the western subspecies of the Purple-crowned Fairy-wren (Malurus coronatus coronatus)

Abstract

Knowledge of the distribution of a species, although fundamental for directing conservation, is often lacking for rare or declining species or those occurring in remote locations. The western subspecies of the Purple-crowned Fairy-wren (Malurus coronatus coronatus) is a riparian habitat specialist of the Kimberley and Victoria River regions of northern Australia. Although listed as vulnerable nationally, there is little information on its current distribution and population trends. We conducted a comprehensive survey across 14 river catchments within the potential distribution of the subspecies, and identified changes in distribution by comparing the results of the survey with historical records. Western Purple-crowned Fairy-wrens were recorded on the Fitzroy, Isdell, Durack, Pentecost, Drysdale and Victoria River systems. The species was not detected in the Ord or the Sale systems despite previous reports, nor was it found in the Carson, Calder, Meda, Forrest, Berkeley or King George catchments. We suggest these last three catchments were wrongly included in previous estimates of the distribution of the species, when in fact Purple-crowned Fairy-wrens were potentially never there. We furthermore identify the populations of Purple-crowned Fairy-wrens most in need of conservation intervention and recommend excluding cattle to prevent further habitat degradation and population declines. These results are a crucial baseline from which to monitor future population trends of the Purple-crowned Fairy-wren and direct conservation management.