![]() ![]() Johnstone and Kirkby (2008) report that, depending on their provenance, Baudin’s Cockatoos may be year-round residents or postnuptial nomads and migrants, with the majority of the population shifting northwards in autumn to the central and northern Jarrah- Marri forest and adjacent areas of the Swan Coastal Plain, before migrating southwards in spring to breeding areas in the Karri forest and southern Jarrah-Marri forest. Our finding of a mean group size of 14.5 birds is similar to the 13 ± 2 Baudin’s Cockatoos reported by Weerheim (2008), who reported group sizes ranging from one to 100 birds. Johnstone and Kirkby (2008, 2009) report that the species, which is typically confined to forest habitats, generally occurs in small flocks of up to 30 birds, and occasionally in larger flocks of up to 50 or aggregations of c. Group sizes for Baudin’s Cockatoos are variable and seasonally dynamic, with marked differences between breeding and non-breeding periods (Johnstone and Kirkby 2008). There were no encounters with Baudin’s Cockatoos recorded in October or November and no encounters with FRTBC in June. Encounters (including non-GDS sightings) with Carnaby’s Cockatoos occurred in all months. At NBG, FRTBC were detected much more frequently than the other species, whereas within the LEA Carnaby’s Cockatoos were detected most frequently (Tables 6 and 7). Detections for Carnaby’s Cockatoos were highest in spring and summer. Detections of Baudin’s Cockatoos were too few to examine for seasonal variation, but they were not detected during summer GDS samples, although present in the study area (based on non-GDS observations) (Figure 3). There were seasonal fluctuations in detections for Carnaby’s Cockatoos but not for FRTBC (Table 7). The sample size for Baudin’s Cockatoos was too small for analysis. In 2009, more Carnaby’s Cockatoos were seen than expected. Within the LEA, Carnaby’s Cockatoos detections fluctuated significantly across the years. For FRTBC, there were fewer detections in 2010 than expected given the sampling intensity. ![]() Despite the low sampling intensity in 2007, more Carnaby’s Cockatoos were seen than expected. ![]()
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