Gliders were thought to eat swift parrots. Cameras showed something different

A recent Commonwealth-funded study is questioning the long-held belief that introduced sugar gliders pose the main threat to Tasmania's critically endangered swift parrots. Researchers Matt Webb and Leanne Wicker employed acoustic monitoring, motion cameras, and glider trapping over two breeding seasons on mainland Tasmania.

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No confirmed predation of swift parrots by sugar gliders was recorded during this study, despite documented visitation to and entry into nest hollows.

Their findings revealed no confirmed cases of sugar gliders killing swift parrots. The study monitored 20 nests across various Tasmanian regions over two breeding seasons. "No confirmed predation of swift parrots by sugar gliders was recorded during this study, despite documented visitation to and entry into nest hollows," the report states. It further notes that gliders were present at, and entered, nests that successfully fledged young, indicating that their presence alone is not a reliable indicator of impact.

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Gliders were detected at, and inside, nests that successfully fledged young, confirming that presence or visitation alone is not a reliable indicator of impact.

Instead, the study found evidence of predation on swift parrots within nests by other birds, including native black currawongs and introduced European starlings. While these birds attacked and killed swift parrots, the study concluded that "no species determined nest success or failure." The researchers attribute these interactions to competition-related aggression and predation, exacerbated by "ongoing habitat loss and fragmentation."

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European starlings attacked and killed swift parrots.

For over a decade, sugar gliders have been widely considered a major threat, with earlier studies suggesting they reduced swift parrot survival rates to as low as 17 percent. However, Dr. Webb stated that these findings did not align with his field experiences. The researchers utilized a "contemporary approach," focusing on nest monitoring and forensic necropsies to understand glider diets and the causes of nest failures. They emphasize that breeding success is influenced by multiple interacting ecological processes, and conservation planning should reflect this complexity.

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A black currawong is among the native birds that were seen to take swift parrot chicks.