White-winged Chough Corcorax Melanorhamphos Research Articles

Bird population responses to wildfire and planned burns in foothill forests of Victoria, Australia

Fires and people have helped shape forest ecosystems. Planned burns can be used to reduce social or ecological risks from wildfires, but we need a better understanding of the ecological effects of planned burns and wildfire over various temporal and spatial scales. Here, two approaches were used to answer various questions about responses of diurnal birds to fire regimes in mixed eucalypt forests in the foothills of Victoria, Australia: what are the effects of planned burns (at two different frequencies and seasons) when applied systematically over many years, and what are the short-term effects of severe wildfire? A long-term experiment examined planned burns in two seasons and at two frequencies on 25 sites in Wombat State Forest in 1984. An opportunistic study compared bird abundance in 33 burnt and 33 unburnt sites in the year after an extensive severe wildfire in Bunyip State Park in 2009. Brief reference is also made to a retrospective study, which provided a longer-term perspective by examining bird abundances at 113 sites in eastern Victoria that had been subject to different regimes over the past 40+ years, addressing questions about the impacts of different fire frequencies and times since fire. This paper considers data from snapshot surveys in 2009–2012. Data from Wombat State Forest showed significant effects of fire treatments for just four of the 27 species analysed (p < 0.05). In frequently burnt sites, Brown Thornbills Acanthiza pusilla (shrub foraging insectivores) and Scarlet Robins Petroica boodang (open-ground insectivores) were least common, and Rufous Whistlers Pachycephala rufiventris (canopy-foraging insectivores) and Australian Magpies Cracticus tibicen (open-ground insectivores) were most common. There was weak evidence that three species were advantaged by burning in autumn rather than spring, and one of them (White-winged Chough Corcorax melanorhamphos, an open-ground insectivore) was rarely recorded except in sites burnt in autumn. Data from Bunyip State Park showed that birds were 77 % less numerous on burnt than unburnt sites in the winter after severe bushfire, but some redistribution had occurred by the next spring, along with an unprecedented spring influx of White-browed Woodswallows Artamus superciliosus (aerial insectivores) to burnt sites from inland Australia. The study shows that planned burns can be conducted in spring or autumn every 3–10 years with only small effects on common forest birds, at least when they are conducted on small areas in a forest with a history of disturbance. Wildfires can have much more dramatic short-term effects on bird populations. The retrospective study suggested that these effects may be short-lived, as such dramatic contrasts were not found between sites burned at different times beyond 3 years. Multiple approaches will be needed to answer key questions about longer-term effects of planned burns and wildfires in order to help reduce risk and conserve biodiversity.

Ian Cecil Robert Rowley 1926–2009

Ian Cecil Robert Rowley 1926–2009

Structural Change of Begging Vocalisations and Vocal Repertoires in Two Hand-raised Australian Passerines, the Little Raven Corvus mellori and White-winged Chough Corcorax melanorhamphos

SummaryChange in vocal structure during development was investigated in two large Australian passerines, a corvid, the Little Raven Corvus mellori and a corcoracid, the White-winged Chough Corcorax melanorhamphos. Begging calls in both species were harsh vocalisations covering a wide frequency range. The major ontogenetic change in begging call structure was in pulse duration. Little Raven begging calls increased in pulse duration with increasing age while White-winged Chough begging calls decreased in duration. In both species pulse duration of begging calls gradually approached the duration of other vocalisations such as alarm, distress and contact calls given by fledglings and juveniles. The vocalisations of the White-winged Chough included both noisy (harsh), pure harmonic and tone vocalisations, while the vocalisations of the Little Raven showed less variation, with most vocalisations having a combined noisy and harmonic structure. In both species, begging calls were very similar in structure to other vocalisations produced in later stages of development, suggesting that the production of begging vocalisations may be important in the development of adult vocalisations.

White-winged Choughs Corcorax melanorhamphos Using a Stick Nest

(1996). White-winged Choughs Corcorax melanorhamphos Using a Stick Nest. Emu - Austral Ornithology: Vol. 96, No. 3, pp. 207-208.