Thanks to all of you that provided sightings of feeding Gang-gangs. In total over 4000 Gang-gang feeding sightings and records was able to be collated. The published report is available for free download on the Australian Bird Study Association website at
https://absa.asn.au/corella-documents/volume-47-2023/

This is the abstract from the paper

"The diet of the endangered Gang-gang Cockatoo Callocephalon fimbriatum has not been well documented. The aim of this investigation was to collate and synthesise information from electronic and written sources to fill this knowledge gap and thus provide information that could assist in the species’ conservation. Four thousand one hundred and thirty five feeding records from across the species’ range were collated from image-based records posted on social media and citizen science platforms, and from the written records of bird observer clubs and bird group databases. There were 275 different food items recorded in these feeding records. Gang-gangs fed on seven main food groups: eucalypt nuts and flowers (43% of all feeding events); berries with relatively large seeds but a small pulp mass (21%); green cones of mainly the Pinaceae and Cupressaceae families (10%); wattles, almost exclusively in spring – early summer and on plants with green pods (8%); soft pods mainly of Liquidamber Liquidamber styraciflua (7%); nuts, mainly walnuts Juglans sp. and oak acorns Quercus sp. (3%), and invertebrates, mainly sawfly Pergidae sp. larvae and lerps Pysllidae sp. (1%). The Gang-gang’s diet varies across its range and this seems to largely reflect the particular food species that are available locally (both planted or indigenous to certain areas). However, there are both regional and overall food preferences. Just twelve taxa accounted for 54% of all feeding events, whilst most other food items were only recorded as being eaten once or twice. Twenty-six percent of the plant species eaten are exotic, which suggests that Gang-gangs can adjust to new food sources. Gang-gangs’ diet is broad and flexible and their food is abundant."

There is now enough information to determine that food availability is not a limiting factor for Gang-gangs, and I don’t intend to continue to do any more work on this area. However it would be good if you can keep adding your records to INaturalist and the Hungry Parrots project as it will enable others to do further future analysis with a larger data set. Already my report is out of date in that you have added additional food items to the 275 I collated. The paper also suggests that analysis of diet using Inaturalist records could be useful for other parrot species.

Thanks again for your contributions to the study

Michael Mulvaney