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2023 Canberra Ornithologists Group Red Hill Woodland Spring Survey
The 25th anniversary survey of Red Hill (Sunday, 24 Sep 2023) was done on a perfect Spring morning, with early high overcast clearing to clear blue skies and no wind. Despite a general lack of flowering, bird diversity and numbers were both above the long-term average for Spring.
Several late winter stragglers or early summer returns were evident, including both Golden and Rufous Whistlers, Grey Fantails, White-throated Gerygones, Noisy Friarbird and Olive-backed Oriole. Yellow-faced and White-naped Honeyeaters were also present despite the early time of day. The cohort of small bush birds included the staple fairy-wrens, Buff-rumped Thornbills and Weebills, as well as widespread but small numbers of Spotted Pardalotes, and a single Striated Pardalote heard, but lacked other Thornbills, and Speckled Warblers were not recorded for a slightly concerning 5th consecutive survey. A nice touch was a gang of 10 Gang-gangs quietly feasting on spent blossoms of Black Wattle (Acacia mearnsii).
A few less usual species made their presence known: an owlet-nightjar called (just the 2nd recorded during these surveys), and at least one Horsfield’s Bronze-Cuckoo was heard sporadically (perhaps surprisingly, only the 7th record).
The only signs of possible breeding were a sole Galah inspecting a hollow, and a pair of Australian Ravens stationed near a nest, though they never actually went to the nest in the time I kept an eye on them.
Overall 38 species were recorded, 34 within the nine survey sites and an additional 4 recorded only between sites. A tally of 424 individuals (both on and between sites) was well above the Spring average of 314.
Although this was the 25th anniversary survey, it was my 101st survey of the Red Hill site as there was an additional survey done in February 2002 to assess the impact of the fires that ravaged the area on the Christmas eve prior. Over the 25 years I’ve been ably assisted by several co-surveyors, but at this point I am again looking for someone to help with the surveys on a regular quarterly basis. If you’re interested, please get in touch at hdpphd.gmail.com
2020 Canberra Ornithologists Group Red Hill Woodland Spring Survey
It was always going to be a low count: the wind off the snow-covered Brindabellas was bitingly cold and the sun, which appeared only occasionally through the 80% cloud cover, was utterly ineffectual in warming things up, birds or fingers. The total tally of 28 species ranks with the lowest for a Red Hill Spring survey, along with 2004, 2012 and 2015, and 6 species below the average over 89 surveys. Total numbers were also below average; there must have been many more hunkered down out of the wind and avoiding detection, especially the smaller birds. The counts would have been even lower were it not for one site, in a small gully comparatively sheltered from the westerly winds, which added several species not recorded anywhere else, including a young Golden Whistler, 9 Yellow-faced Honeyeaters, several Grey Fantails, a Noisy Friarbbird, and a silently foraging White-throated Gerygone. The gerygone was the highlight of the morning, being only the fourth time in 89 surveys that the species has been recorded. Only indications of breeding were a family of Australian Ravens (parents plus three fledged young), and a couple of choughs on a nest.Harvey Perkins (and Stuart Harris)
2017 Canberra Ornithologists Group Red Hill Woodland Autumn Survey
Saturday morning at Red Hill for the Autumn Woodland Survey on 25 March was mild and calm with both post-fog cloud and hot air balloons rising slowly and drifting away. It was a pleasant survey and the birds seemed to be quite active, though the total number of species recorded was spot on average (23 within the nine sites, and a further 8 recorded between sites) and the total number of individuals (448) just slightly higher than average. No classic mixed feeding flocks, but the number of small birds was boosted somewhat by a group of Striated and Spotted Pardalotes. Otherwise, the most notable aspect of the survey was the diversity (9 species) and prevalence of parrots and cockatoos, including a couple of Yellow-tailed Black Cockatoos, three Rainbow Lorikeets, and 40 very active and vocal Australian King Parrots. No sign of any smaller honeyeaters, and little of migrating species, other than the 11 Grey Fantails and flock of about 35 Silvereyes. Satin Bowerbirds (9 – highest record to date) were seen in several locations, including at the top car park where, together with Australian Ravens and Pied Currawongs, they were feasting quietly on kurrajong seeds.
2016 Canberra Ornithologists Group Red Hill Woodland Spring Survey
The spring survey of Red Hill was done under perfect conditions, mild and calm, on Saturday 24 September. The whole site was quite active, and we rang up a total of 37 species (26 or 70% of them within sites), above the average of 33.9 over 17 surveys. Although larger birds again predominated, especially cockatoos & parrots, and magpies, currawongs and ravens, there was a smattering of smaller bush birds including both pardalotes and three thornbill species, a couple of Golden Whistlers and a pair of Rufous Whistlers, and a residue of Grey Fantails. Yellow-faced Honeyeaters were evident with several small groups of 2-6 birds moving through, even before our 7:00 am start. Olive-backed Orioles also heralded the spring weather, with 6 recorded (the highest number recorded to date during these surveys), and a Sacred Kingfisher was heard over towards the golf course. Magpie-larks also topped their recorded numbers with 17, as did Black-faced Cuckoo-shrikes with 13 recorded. Only Crimson Rosellas, Eastern Rosellas and Noisy Miners showed any inclination towards nesting. Sadly, White-throated Treecreepers appear to have disappeared from the site – they were regular from the first survey (September 1998) through to autumn 2010, but since then there has only been a single record, on 29 March 2015.Dr Harvey Perkins
2016 Canberra Ornithologists Group Red Hill Woodland Winter Survey
Complications of availability and weather meant I did the Red Hill WOO survey over the mornings of Tuesday 21 June and Wednesday 22 June, barely avoiding the misting rain that enveloped the mountain as I finished up at the final site. Although it seemed very ‘slow’, overall the numbers of birds (294) and species (30) recorded were spot on average for a Red Hill winter survey. 25 of the 30 species were recorded within survey sites. Diversity was boosted from what would otherwise have been a low total by a couple of roving feeding flocks of small birds including a pair of Scarlet Robins. Little Corellas continue to increase (total of 44 eclipsing the previous high of 11), and Rainbow Lorikeets were also recorded and are becoming quite regular. Choughs were recorded for just the 6th time over the 71 surveys, and sadly consisted of gangs of just 4 and 6 birds; and Wood Ducks made their regular winter appearance in the dead trees. Other highlights included a single Mistletoebird (only the site’s 4th record; and it would appear that this species is a feature of this year’s winter surveys) and a brilliant male Golden Whistler whose colour and contact call brightened the gloom.Dr Harvey Perkins
2016 Canberra Ornithologists Group Red Hill Woodland Autumn Survey
The Red Hill survey was done on a cooler but pleasant morning on Sunday 20 March. Numbers of species (29) and individuals (360) were pretty typical for an autumn survey, but diversity within sites was slightly up on average. There was a distinct shortage of honeyeaters (only Noisy Miner, Red Wattlebird and Noisy Friarbird recorded), but there were several loose mixed foraging flocks about, dominated by Grey Fantails, of which 38 were recorded, eclipsing the previous maximum number recorded of 33 in autumn of 2012. Other participants included young and female Golden Whistlers, Buff-rumped and Brown Thornbills, both pardalotes, a couple of Weebills and a Speckled Warbler. A party of six Yellow-rumped Thornbills were, surprisingly, the first of the species to be recorded since December 2014. Little Corellas continue to increase slowly, with eleven recorded on this survey, the largest number so far. A couple of widely separated male Scarlet Robins were probably the highlights of the morning.Harvey Perkins &Stuart Harris
Stuart Harris and Harvey Perkins did the Spring survey of Red Hill on the beautiful calm and sunny morning of Sunday 27 September 2015. The number of species (33) and total individuals (317) were both pretty close to average for spring surveys at this site. Intent to breed was recorded for four species: both Crimson and Eastern Rosellas were seen inspecting hollows; two active Noisy Miner nests were seen, one with a bird sitting, the other, built only about 2 metres up in a small sapling, contained 3 eggs; and a pair of kookaburras was seen courting / pair-bonding, and finally copulating. The latter was something I’d not seen before. The pair would sidle up to each other on a branch of the large gum tree, bills almost touching, then each in turn would fly quickly and briefly to the nest hollow entrance about 3-4 metres away before returning to the branch, in what resembled a game of touch-tag. This lasted for a minute or so, perhaps a dozen or so sorties each, before they consummated their commitment through copulation. Unfortunately, their coitus was rudely interrupted by one of the three other kookaburras that were in the vicinity which flew directly at the mating pair such that all three were unbalanced and flew off to different parts of the tree.Other signs of spring included the return of Noisy Friarbirds (3), a single Yellow-faced Honeyeater heading west, 6 Black-faced Cuckoo-shrikes, singles of both Golden and Rufous Whistlers and 8 Grey Fantails. Raven activity was also pronounced, with 19 Australian Ravens recorded across the site (about twice as many as you might normally expect) and they were very vocal and frequently obstreperous, though no sign of breeding activity was noted.
2015 The ACT Government has declared the Scarlet Robin, which can be spotted on Red Hill, vulnerable. More…
2015 Canberra Ornithologists Group Red Hill Woodland Winter Survey
The results of a survey by the Canberra Ornithologist Group (COG) is shown below:
Stuart Harris and Harvey Perkins did the winter Woodland survey of Red Hill on Sunday 28 June 2015, a foggy, cold and damp morning, though the fog lifted over the course of the survey with the first patches of blue sky emerging about 10:00 am. There was little activity to begin with and diversity would have been well below average, even for winter, had it not been for a mixed feeding flock moving about at the last two sites. This added some interesting birds including a pair of Scarlet Robins, Speckled Warbler, and a few young Golden Whistlers and Grey Shrike-thrushes. Other less commonly recorded birds included a female Common Bronzewing (the 8th record over 67 surveys), and a White-plumed Honeyeater (only the 4th record, all in winter). Also of interest were the Australian Wood Ducks, 7 of them, all up in trees calling conspicuously. Several Eastern Spinebills and White-eared Honeyeaters further represented the winter honeyeaters for the site, along with the odd Red Wattlebird. Most of the species were actually recorded at the nine individual sites, with only three species recorded additionally between sites. So what started off as a quite dull (!) survey ended up quite successful and pleasant.
2013 Canberra Ornithologists Group Red Hill Woodland Survey
Sunday March 16 2013. The weather appears to have had an impact, with quite cool and windy conditions. Stuart Harris and Harvey Perkins of COG logged the lowest survey result for the fourteen and a half years of Red Hill surveys. The total of 22 species is the equal lowest on record (and well below the average of 32 species), and a sum total of just 150 individual birds is eight fewer than the previous low of 158 in the winter of 2007 and well below the average of 370 for autumn surveys (or 308 for all seasons).
Magpies, ravens, King Parrots and Noisy Miners were recorded in expected numbers, but everything else, even obvious residents such as the rosellas, produced lower than normal tallies. Small passerines were either scarce or inconspicuous with just a few Superb Fairy-wrens, weebills and pardalotes, and the odd Grey Fantail and Yellow-rumped Thornbill recorded. Recent hazard reduction burns at several sites probably didn’t help, and one site produced a nil return. A couple of highlights included at least a pair of Collared Sparrowhawks, and a pair of galahs checking out a hollow. A single immature Golden Whistler was the only evidence of possible autumn movements.
It is now exactly three years since either White-throated Treecreepers or Red-browed Finches, both species that used to be regular, have been recorded during the surveys.
2011 Canberra Ornithologists Group Red Hill Woodland survey
The survey was done over two mornings – the southern sites (6-9) in cool but clear and calm conditions on Saturday morning, 25 June 2011, and the northern sites the following morning in cold and frosty conditions. Overall diversity and numbers were marginally higher than average, with 31 species recorded for the whole site (mean over 13 winter surveys of 29.5). Species variety was also typical for winter but no mixed feeding flocks were observed and numbers of small birds generally were low.
The most unexpected sighting was a pair of vocal Rainbow Lorikeets that shot through site 9, seemingly on their way from Garran to Forrest. This is the first time the species has been recorded during the Red Hill surveys, and interestingly coincides with a report of a pair of Rainbow Lorikeets in Garran on June 27 2011. Other species to spark a little more interest were a Nankeen Kestrel, a halfway intermediate Crimson/Eastern Rosella hybrid (“paired” with a full Crimson Rosella as seems the norm on Red Hill) and a single White-plumed Honeyeater.
Dr Michael Mulvaney, August 2022
The Gang-gang Cockatoo Callocephalon fimbriatum was recently (March 2022) listed as a nationally endangered species. Red Hill Nature Reserve, Canberra, is a stronghold of this species, with half of all known nest trees occurring on or in the close vicinity of Red Hill. Red Hill Regenerators are leaders in Gang-gang research and are administrating several ongoing citizen science research projects, both focused on Red Hill and nationally. We are always looking for more people to help us in this research.
Gang-gangs are considered endangered as the population has declined by approximately 69% over three generations (approximately 21 years). This decline is measured by the relative occurrence of Gang-gangs recorded in surveys across the birds’ range over the decades of observed decline. In addition to this continuous decline in population numbers, the species also suffered mortality and habitat loss during the 2019/2020 wildfires. Estimates of the species’ distribution impacted by fire range from 28 to 36%, with an estimated 10% of the population killed by these fires (Commonwealth Australia 2022 – draft recovery plan). Canberra’s (including Red Hill’s population) appears steady or slightly increasing.
In addition to fire the main reasons why Gang-gangs are thought to be in national decline are:
- loss of habitat (particularly of hollow bearing trees);
- climate change (Gang-gangs are Australia’s only wholly temperate cockatoo and may not cope well with higher temperatures); and
- Competition from other hollow nesters, particularly Sulphur Crested Cockatoos, Rainbow Lorikeets, feral bees and Brushtail Possums.
Nesting ecology research
Red Hill Regenerators first noticed Gang-gangs nesting on Red Hill in 2017. At that time there was only one other nest tree of this cockatoo recorded anywhere in Australia and nearly all that was known about Gang-gang’s breeding ecology was from observation of aviary birds.
In order to learn how we could best look after our wild breeding birds and to place in context how significant Red Hill may be for the species, we began a search for further nest trees and once found, spent many hours observing their behaviour, interactions with other species and nesting success.
We asked people to load into the citizen science Canberra Nature Map and INaturalist platforms any observation of Gang-gangs showing an interest in a tree hollow. By the 2021-2022 season, 950 hollow activity sightings had been recorded with 700 of these in the Canberra area. More than half of the hollows recorded were further monitored by repeated on-ground visits or examined with a pole camera. This has resulted in the identification of 61 nests in 58 nest trees. Fifty-two of the nests are within the Canberra area and nine are elsewhere (two at Campbelltown, one near Berry, one near Moruya, one near Cooma, one near Tumbarumba, two in Wombat State Forest near Daylesford and one in Melbourne),
The finding and observation of nesting hollows have yielded the following:
- Wild birds, like the previously studied caged ones, have a 4 week incubation period, with chicks taking a further 6-8 weeks to fledge.
- On average, nest hollows are 55cm deep and have entrances that are 21cm high and 15cm wide. These measurements have been utilised by others to build appropriate nest boxes, which are currently being trialled. To date, there are no records of wild Gang-gangs successfully using nest boxes.
- A wide range of hollow bearing eucalypt trees are utilised for nesting.
- In dry hot years only trunk or major limb hollows in living trees are utilised but in cooler wetter years, hollows in less well insulated dead trees may be used.
- Most nest trees that have been found are clustered within a few hundred metres of other nests, or are in woodland, open forest, and within 250m of an urban edge.
- Nesting birds are very quiet and secretive around nests. Males tend to do the day shift on eggs and young chicks, and females always the night. Changeover typically involves one soft “get ready” call by the incoming bird and is over in seconds.
- Date of fledging is related to altitude and there can be as much as two months difference between the time that chicks leave a nest. Those at low altitudes fledge before those at higher locations.
- Three to eleven days prior to fledging, parents will only feed chicks at the hollow entrance, encouraging chicks to move to the hollow rim where they can stretch and practice flapping wings. This can sometimes result in a chick falling from or being knocked to the ground below by a siblings’ flapping wings. On the three occasions when fallen chicks have been put back in a hollow they have all successfully fledged, including one chick that was taken by a finder (not part of the research team) to a nearby vet, where it spent the night, prior to replacement in its hollow.
- High temperatures or smoky conditions seem to encourage chicks to prematurely move to the hollow rim or make them unsteady and more prone to fall. At least one chick seems to have died in a hollow during an extreme heat event.
- For every ten male chicks successfully fledged there are seven female fledglings.
- One to three eggs, but usually two, are laid in a nest. The fledging success rate per nest is around 70%.
- If a nest hollow is used one year there is a 50% chance that it will be used the next. In any one breeding season about 30% of known nest trees are used.
- Around 9% of hollows that Gang-gangs showed an interest in within the Canberra area, were used for nesting. Gang-gangs prepare nest hollows by lining the base with bit-sized chunks of bark. Some Gang-gang pairs prepare multiple hollows in the same season.
- Around 9% of hollows of gang-gang interest were flooded and usually held 5cm or more of water. These flooded hollows are an important Gang-gang water source, with certain drink trees being utilised across the six years of study.
- About 47% of hollows of interest in the Canberra area where completely empty during the breeding season and only 4% were occupied by other hollow competing parrots or cockatoos.
- Brushtail Possums occupied between 11-17% of the 191 hollows of Gang-gang interest inspected in the Canberra area. They are the biggest hollow competitor and probably the major predator taking both eggs and chicks.
“Gang-gang Cockatoo diet as assessed by camera images and written records“. Michael Mulvaney & Isobel Booksmythe, Australian Bird Study Association, Corella, 2023, 47: 8-15. https://absa.asn.au/wp-content/uploads/2023/04/4_V47_Pg8-15_GangGangCockatoo_V2.pdf
4135 Gang-gang Cockatoo Callocephalon fimbriatum feeding records were collated by Red Hill Regenerators 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 defined as 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.
Birdlife Australia placed on their website on 23 September 2020, an article about the Gang Gang which refers to a study undertaken on Red Hill and environs about Gang Gang nesting habits. More…
The Red Hill Regenerators has published a handy guide for those undertaking Gang gang observations, titled ‘Gang gang nesting tell tale behaviours, 2022′, by Mulvaney M J, Tyrrell T and Davey C
The full report and data files are here:
- Gang-gang diet as assessed by image and written feeding records (PDF)
- Appendix 1. Food species list by bioregion (XLS)
- Gang-gang feeding records (XLS)
The following birds were recorded on Red Hill by members of the Canberra Ornithologists Group (COG), between 2007 and 2010
Australian Wood Duck
Little Black Cormorant
Little Pied Cormorant
Noisy Miner (Should Noisy Miners be culled to protect other birds. Read research here and report here)
Pacific Black Duck