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 Already my report is out of date in that you have added additional food items to the 275 I collated.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

This project aims to better understand the population genetics of Gang-gang Cockatoos iacross their range through feather collection.

Feathers contain genetic information unique to an individual. They provide insights into the biology and ecology of birds that are otherwise challenging to sample, and in a way that is not intrusive.

By learning about the genetic variability of Gang-gangs, we can estimate their ‘effective population size’. Knowing the population size of a species, and monitoring changes to this over time, can directly inform planning and implementing conservation actions. Genetic information extracted from Gang-gang feathers may also provide insights into their habitat use, mating systems and conservation status across their range.

To see how you can help go to

https://www.environment.act.gov.au/nature-conservation/conservation-and-ecological-communities/gang-gang-cockatoo-feather-collection-project#:~:text=This%20project%20aims%20to%20better,information%20unique%20to%20an%20individual.

We learnt a lot about Gang-gang movements from citizen science reported sightings of "Baldy" a male Gang-gang with a distinctively damaged crest, who was raising two chicks in Canberra bushland. Baldy has now nearly fully grown back his crest and is now not so distinctive. However, we have another noticeable Gang-gang for you to look out for and please report. She has a mishappen beak which looks like a very long uncut finger nail. She has been reported from South Canberra but may breed elsewhere.

https://canberra.naturemapr.org/sightings/4439813#Comments

Thanks Michael Mulvaney

Thanks you to all those that contributed records to the Gang-gang diet study. A summary of the findings is provided below. The full report can be read and accessed at the bottom of this page

http://redhillregenerators.org.au/?page_id=277

In summary, 4135 Gang-gang Cockatoo feeding records were collated from image-based records posted on social media and citizen science platforms and from written records of bird observer clubs and bird group databases. The records covered the whole Gang-gang range but were clustered in and around the larger urban centres, particularly Canberra and Melbourne.

There were 275 food items recorded in the 16,798 feeding events. A feeding event being the number of Gang-gangs in an image or written record multiplied by the number of days over which the feeding event was recorded. Three taxa, Blue Gum Eucalyptus globulus, Hawthorn Crataegus sp. and Liquidamber Liquidambar styraciflua comprise a third of all recorded feeding events. The top twelve taxa account for 54% of all feeding events. Over half of the food items were recorded as being eaten only once or twice amongst the total record. Gang-gangs sample a wide range of foods, and have a varied diet, but the bulk of their observed feeding was on a few taxa.

Of the plant species eaten 26% are exotic, which suggests Gang-gangs have adaptability to new food sources. Targeted or main food species vary across regions and seem to be related to availability and a degree of preference. For example non-local Blue Gums comprise 58% of the eucalypt feeding records in Canberra, but other eucalypts that Gang-gangs feed on are much more numerous in surrounding bushland and similar in number re amount of planting. The Gang-gang diet is varied and food is abundant, and the Gang-gang adapts to what is available. It seems unlikely that food availability is a limiting factor for this species.

Gang-gangs eat from seven main food groups. These are, in terms of the proportions that they constitute to the recorded feeding events:
• eucalypt gum nuts and flowers (43%);
• berries with relatively large seeds but small fruits (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 from a variety of tree and shrub species, but mainly Liquidamber (7%);
• nuts mainly walnuts Juglans sp. and oak Quercus sp. (3%);
• and invertebrates mainly sawfly and lerps (1%).

Eating from the range of food groups seems to be of importance. Amongst the ten most fed-on taxa all of the first five of the above food groups are included.

Wattles are the main food item in November and December. Wattles remain a major food item in January but exotic berries become the main food item through February and March. Gum nuts and flowers are the major food item from April to October. They peak as the major proportion of the total diet from May to August.

A recognisable crest-damaged male Gang-gang feeding two chicks in a nest in Canberra bushland was observed foraging 3.9km from the nest as well as three other closer locations. He repeatedly fed on Sunflower Helianthus annuus seed at one location. This may be of concern as overfeeding on Sunflowers by caged Gang-gangs can lead to infertility and other health problems.

Feeding records, during the September – January breeding season and within 4km of any one of 49 known nest trees in the Canberra area, were found to have a greater proportion of gum nut/flower feeding events, and less wattle feeding than those recorded more than 4km away from known nests.

The Gang-gang diet differs across its range and this seems to largely reflect the food species that are available locally (both planted or indigenous to certain areas). However there also appear to be some cultural differences between populations with some widespread species such as Water Milfoil Myriophyllum sp., Dogwoods Cornus sp. or White Poplar Populus alba only being eaten or predominately so in one bioregion.

Collection bias limits comparisons being made between tall forests (where few records were obtained) and urban and peri-urban woodland and dry forest habitats (where the bulk of records were obtained). However, the data demonstrates that the latter habitats are important for foraging and breeding Gang-gangs. These habitats also support the vast majority of currently known nest trees.

Thank you.

Thanks to the 227 of you that have provided sightings of feeding Gang-gangs via INaturalist. I recently did an analysis of the 1800 records I have so far received for Birdlife Australia as part of their preparation of a program to encourage residents and schools to plant Gang-gang friendly plants in their gardens and grounds. The 1800 sightings included 181 food items and recorded 7230 feeding events. (The number of Gang-gangs recorded by a sighting, multiplied by the number of days over which the feeding occurred.).

About 30% of the feeding is on exotic plants. About 50% of the records are from the Canberra area. I hope that by the end of the study (June 2022) I will be able to do seperate regional guides. So please keep you observations coming.

As discussed previously Gang-gangs seem to feed from five main food groups. The current data provides the following information

1. Eucalyptus and other Myrtaceae buds, fruit and flowers (56 Eucalypts, 2 Angophora, 5 corymbia, 1 leptospermum and 2 Melaleucas) - 44% of sightings, 50% of events
   The top ten species are
   Eucalyptus globulus asp bicostata
   Eucalyptus globulus spp maidenii
   Eucalyptus bridgesiana
   Eucalyptus macrorhyncha
   Eucalyptus viminalis
   Eucalyptus globulus sip globulus
   Eucalyptus pauciflora
   Eucalyptus sieberi
   Eucalyptus mannifera
   Corymbia gummifera
   Eucalyptus sideroxylon

2. Wattles (35 species recorded) 9% of sightings or 5% of events the top 3 are all bipinnate species
   
   Acacia dealbata
   Acacia baileyana
   Acacia mearnsii

3. Cones and Pods (32 species) 16% of sightings and 20% of events. the top five are
   Liquidambar styraciflua
   Cupressus sempervirens
   Callitris enlicheri
   Cupressus arizonica
   Cupressus macrocarpa

4. Relatively small berries with relatively large seeds (31 species) 26% of sightings and 21% of events, the top six are
   Crataegus monogyna/laevigata
   Cotoneaster glaucophyllus
   Pistacia chinensis
   Melia azerderach
   Persoonia linearis
   Persoonia pinifolia

5. There are eight Insects and Acacia Fungal galls as food items they only make up 2% of sightings and 1% of events. The majority of records are of sawfly larvae.

Thanks again for your contribution

Michael Mulvaney

Thanks very much to the 195 of you that have added Gang-gang records to the Hungry Parrots project. You have contributed about a third of all the Gang-gang feeding records collected to date. Earlier this week we passed 150 distinct food items of which 66% are native species, 28% are exotic species and 5% are invertebrates. What is intriguing is that many of the food items are only eaten in one part of the Gang-gangs range. For example of the 1400 records that we have, Hughes (a suburb of Canberra) is the only place where Gang-gangs have been recorded as eating cicadas while Penrose in the Southern Highlands is the only place where Gang-gangs have been recorded eating the fleshy fruit of the domestic apple. Whether this apparent diet specificacy is due to not having a large enough sampling, or just reflects what is available within a particular area, or relates to local population preferences is uncertain, but your continued records will help throw light on the situation as well as telling us much more about Gang-Gang diet.

Thanks again for your help in this research

Michael Mulvaney

Dear Hungry Parrot Project contributor

I have already messaged many of you about the Gang-gang citizen science projects and how your Inaturalist sightings are helping us expand our knowledge on this truly magnificent Cockatoo. I also want to publicly thank Erika Roper for allowing me to utilise the Hungry Parrot team and your sightings. For those for which this is my first contact, hi, please keep up your reporting of all parrot feeding, but of course I would like you to pay particular attention to the Gang-Gang. Within the last three decades there has been a 69% decline in its reporting rate across its range, while the 1999/2000 fires significantly impact about 30% of its habitat.

I write to both thank you for the sightings you have already contributed to Hungry Parrots and to encourage you to keep those sightings coming and to dig out and lodge old images you may have. To date about 350 separate Gang-gang feeding sightings have been lodged. I have combined these with a similar number of sightings recorded via the Naturemapr network and about 600 feeding records from the Canberra Ornithologists Group’s The Gang-gang Cockatoo Citizen Science Survey March 2014 – February 2015. A special thanks if you also contributed to this survey.

There are a tens of records, many of them eucalyptus, that I still have work to do to identify to species level. Where I can, I will also extract feeding events from the records, that is the food item captured in the image x number of birds x number of consecutive days spent feeding. Please, where you can, include this information in the comments section of future sightings .The current “highest scores” are 25 birds feeding together and another records states continuous daily feeding over 3 weeks.

To date we have 1180 feeding sightings and they are telling us that the Gang-gang has wide ranging tastes feeding on 132 different plant taxa across 25 different plant families. They are mainly eating flower buds and seed pods but also eat blossom, leaf buds, fruits and seeds. Mostly they are feeding on trees and shrubs but there are images of them feeding on the fruits and seeds of Devils Twine (Cassytha species) and one image of a male eating the head of a Ribwort (Plantago lanceolata).

The major families from which food is obtained is shown below, together with the genus targeted and the number of species fed on within each genus.

Myrtaceae (Eucalyptus 40, Corymbia 4, Leptospermum 2, Melaleuca 2 and Angophera 1)
Fabaceae (Acacia 25, Cercis 1 and Sophora 1)
Rosaeace (Cotoneaster 3, Pyrus 3, Crataegus 2, Malus 2, Prunus 1 and Sorbus 1)
Cupressaceae (Cupressus 4, Callitris 2, Chamaecyparis 1 and Cryptomeria 1)
Proteaceae (Hakea 4, Persoonia 4 and Banksia 1).

Just over 2% (27 sightings) of all food images are invertebrates, with sawflies making up half of these (13). Acacia (4) and eucalypt galls (2), Lerps (5) and Red-eye Cicada (2) are eaten. There is also one sighting of a pair feeding on Acacia fungal galls.

This catholic omnivorous diet seems to suggest that the Gang-gang would have a large potential food supply and that starvation or poor nutrition is unlikely to be a factor in its dramatic recent national decline. However nearly 70% of all food item sightings are from just four genera. Eucalypts comprise 50% of all sightings, Acacias 8%, Liquidamber styraciflua 6% and Pistacia chinensis 4%. Rosaeace are the food item in 12% of sightings and Cupressaceae are in 4%.

Around 2/3 of all records are from Canberra, but when only sightings from native vegetation away from Canberra, are considered there are more than 50 species fed on, with Eucalypts making up a large majority of the food item sightings. In both the Canberra and wider records certain species and types of both Eucalypts and Acacias are targeted above others. It is hoped that with your further reporting of food items we can have a good understanding of exactly what species are being targeted and build this information into guidelines for re-establishment or enhancement of Gang-gang habitat. The information should also enable use to inform people in cities and rural blocks what species they can plant if they want a Gang-gang garden.

I hope you collectively will report over 3,000 Gang-gang food item sightings by the middle of next year, and it would be fantastic to have the current level of Canberra’s documentation reported in other parts of the Gang-gangs range. But you Canberra people are special and I also want you to keep contributing sightings. You are special because:
• At a local scale the Australian Botanic Gardens is a field experiment fifty years in the making with one of the greatest collections of eucalypts and acacias in the country providing a real test of Gang-gang species preferences for these two key food groups;
• At a wider scale the location and abundance of street trees and public plantings is recorded while the level of private plantings has been researched meaning that it is again possible to test that Gang-gang food preference is not just reflecting the relative abundance of plant species; and
• We know of 35 nest trees in the Canberra area, of which 12-16 will be used each year. If we receive a large number of sightings we can study whether the food items selected close to nest sites is different to that observed in areas where birds are not nesting. This may provide insight in to how breeding success could be enhanced.

Thanks for already contributing to our knowledge on what Gang-gangs are eating and I hope I am not being too pushy in asking you to go out and get more.

Cheers

Michael Mulvaney