Bird species numbers act as an indicator of biodiversity richness
By Tanya Loos and Grant Palmer
Our very first visitor: Yellow-faced Honeyeater.
We can use bird monitoring to show that bird diversity and numbers ( species richness and abundance) have increased at the site overall, as a result of the revegetation and regeneration of a diverse suite of native plant species. This will be easy to show, as we can graph the increase in bird species and occurrence over time, as the plantation grows. A record 46 species was seen at the spring 2020 bird survey.
The first bird seen using the south site was the Yellow-faced Honeyeater, Lichenostomus chrysops (pictured) in October 2011. A common honeyeater in the area, it has been observed on most of the group’s surveys. A flock of about eight birds were foraging on the healthy young blue gum seedlings, which are about waist height. The honeyeaters would forage for a while, then back to the nearby remnant, then return to the open area to feed again on the insects in the young trees. On the June 2013 survey, a number of birds were observed foraging on the wattles and young eucalypts in the South ImLal site: namely, Brown Thornbill, Grey Shrike-thrush, Superb Fairy-wren and Grey Fantail. Birds have been seen in the biorich plantation at every survey since.
We have now carried out over 35 surveys on the site, which are held on a seasonal basis, with over 90 species having been observed. Surveys are led by ornithologist Dr Grant Palmer a Senior Lecturer in the Centre for Environmental Management at Federation University, Ballarat. Data from the bird surveys is shared with BirdLife Australia. Grant Palmer's write-up of the latest autumn survey 2024 follows.
The first bird seen using the south site was the Yellow-faced Honeyeater, Lichenostomus chrysops (pictured) in October 2011. A common honeyeater in the area, it has been observed on most of the group’s surveys. A flock of about eight birds were foraging on the healthy young blue gum seedlings, which are about waist height. The honeyeaters would forage for a while, then back to the nearby remnant, then return to the open area to feed again on the insects in the young trees. On the June 2013 survey, a number of birds were observed foraging on the wattles and young eucalypts in the South ImLal site: namely, Brown Thornbill, Grey Shrike-thrush, Superb Fairy-wren and Grey Fantail. Birds have been seen in the biorich plantation at every survey since.
We have now carried out over 35 surveys on the site, which are held on a seasonal basis, with over 90 species having been observed. Surveys are led by ornithologist Dr Grant Palmer a Senior Lecturer in the Centre for Environmental Management at Federation University, Ballarat. Data from the bird surveys is shared with BirdLife Australia. Grant Palmer's write-up of the latest autumn survey 2024 follows.
Autumn 2024 bird survey – resident birds resume their dominance following departure of migrants
Autumn bird surveys are always an interesting time in south-eastern Australia as resident birds resume their dominance following the departure of spring-summer migrants, including various honeyeaters, cuckoos and whistlers. Such spring-summer migrants are often numerically dominant in the bird community, as well as being loud and busy as they navigate the breeding period. But, when they depart, the bird community undergoes a bit of reset, as the hardy residents remain and prepare to make it through winter before being able to engage in breeding activity during the coming spring.
A feature of autumn bird communities is the influx of young birds into the community from the recent breeding period. In the autumn season, before the next breeding period, many birds are less ‘territory’ bound, less paired up with breeding partners and generally much calmer, as the stresses of the breeding period have relaxed. Food may also be harder to come by during this season as peak periods of plant production, including flowering and nectar, and invertebrate activity wanes. These conditions give rise to the mixed-species foraging flocks that are a prominent feature during autumn. These clusters of species move through an area feeding together in harmony, increasing foraging efficiency and likely also reducing their predation risk (i.e. safety in numbers).
During our recent autumn survey we observed a good number of species, seeing 31 species in total as we walked our usual loop. While this number might be less than you would expect during spring and summer, it provides good evidence that the Biorich plantings and other habitat features are supporting a diversity of resident species. There were good numbers of resident insectivores observed, including Brown and Striated Thornbills, Grey Fantail (numerous), Grey Shrike Thrush, Golden Whistler, Superb Fairy-wren (lots) and Spotted and Striated Pardalotes. Honeyeaters were less abundant than at other times through the year, but good numbers of Red Wattlebird and White -eared Honeyeater were present. Yellow-faced Honeyeater and White-naped Honeyeater were still present, with most of their population leaving this region to overwinter in more northern parts of Australia. These species were all observed using the biorich plantings which are now maturing and providing the resources and habitat complexity that these birds crave.
Numbers of aquatic birds using the wetland were less than at other times. Australian Wood Duck, Pacific Black were few, while just three Eurasian Coots were observed when at other times many more individuals have occurred. There was a pair of Masked Lapwings on the muddy western shoreline and a lone White-faced Heron patrolling the shallows. A single Hoary-headed Grebe cut a lonely figure out in the middle. The usually present Swamp Harrier eluded us.
There were notable observations as we wandered. A group of 15 Purple-crowned Lorikeets, burst through at canopy height, buzzing as they passed. A Grey Butcherbird provided great views out on a dead limb, intermittingly giving its melodious song. Early in the walk a suspected Peregrine Falcon flew past overhead and at speed, instigating the alarm calls of several species. And three Yellow-tailed Black-Cockatoos drifting overhead with their wailing calls were welcome as always.
As we walked around, moving between different patches of habitats, the ‘regulars’ were also encountered, including Australian Magpie, Crimson Rosella, Grey Currawong and White-throated Treecreeper. Surprisingly, no ravens, Eastern Rosellas or Long-billed Corellas were observed during the morning, but that happens; sometimes the birds just aren’t where you are looking at the time!
So all in all, a very rewarding morning’s bird-watching in a revegetated and restored site that is really starting to develop in habitat value as the vegetation matures. It will continue to be fascinating exploring the seasonal changes and year to year variations over coming years.
By Grant Palmer
Autumn bird surveys are always an interesting time in south-eastern Australia as resident birds resume their dominance following the departure of spring-summer migrants, including various honeyeaters, cuckoos and whistlers. Such spring-summer migrants are often numerically dominant in the bird community, as well as being loud and busy as they navigate the breeding period. But, when they depart, the bird community undergoes a bit of reset, as the hardy residents remain and prepare to make it through winter before being able to engage in breeding activity during the coming spring.
A feature of autumn bird communities is the influx of young birds into the community from the recent breeding period. In the autumn season, before the next breeding period, many birds are less ‘territory’ bound, less paired up with breeding partners and generally much calmer, as the stresses of the breeding period have relaxed. Food may also be harder to come by during this season as peak periods of plant production, including flowering and nectar, and invertebrate activity wanes. These conditions give rise to the mixed-species foraging flocks that are a prominent feature during autumn. These clusters of species move through an area feeding together in harmony, increasing foraging efficiency and likely also reducing their predation risk (i.e. safety in numbers).
During our recent autumn survey we observed a good number of species, seeing 31 species in total as we walked our usual loop. While this number might be less than you would expect during spring and summer, it provides good evidence that the Biorich plantings and other habitat features are supporting a diversity of resident species. There were good numbers of resident insectivores observed, including Brown and Striated Thornbills, Grey Fantail (numerous), Grey Shrike Thrush, Golden Whistler, Superb Fairy-wren (lots) and Spotted and Striated Pardalotes. Honeyeaters were less abundant than at other times through the year, but good numbers of Red Wattlebird and White -eared Honeyeater were present. Yellow-faced Honeyeater and White-naped Honeyeater were still present, with most of their population leaving this region to overwinter in more northern parts of Australia. These species were all observed using the biorich plantings which are now maturing and providing the resources and habitat complexity that these birds crave.
Numbers of aquatic birds using the wetland were less than at other times. Australian Wood Duck, Pacific Black were few, while just three Eurasian Coots were observed when at other times many more individuals have occurred. There was a pair of Masked Lapwings on the muddy western shoreline and a lone White-faced Heron patrolling the shallows. A single Hoary-headed Grebe cut a lonely figure out in the middle. The usually present Swamp Harrier eluded us.
There were notable observations as we wandered. A group of 15 Purple-crowned Lorikeets, burst through at canopy height, buzzing as they passed. A Grey Butcherbird provided great views out on a dead limb, intermittingly giving its melodious song. Early in the walk a suspected Peregrine Falcon flew past overhead and at speed, instigating the alarm calls of several species. And three Yellow-tailed Black-Cockatoos drifting overhead with their wailing calls were welcome as always.
As we walked around, moving between different patches of habitats, the ‘regulars’ were also encountered, including Australian Magpie, Crimson Rosella, Grey Currawong and White-throated Treecreeper. Surprisingly, no ravens, Eastern Rosellas or Long-billed Corellas were observed during the morning, but that happens; sometimes the birds just aren’t where you are looking at the time!
So all in all, a very rewarding morning’s bird-watching in a revegetated and restored site that is really starting to develop in habitat value as the vegetation matures. It will continue to be fascinating exploring the seasonal changes and year to year variations over coming years.
By Grant Palmer
Record number of 46 species recorded in the spring 2020 bird survey
Watching a pair of swamp harriers - see below.
Hopes were always high for a very productive spring bird survey at the ImLal Biorich site following the wet winter and pleasant survey conditions on the day, and the small group of birdos were not disappointed – a huge tally of 46 species was recorded along our usual 90-minute circuit! This is an impressive number of species for a single survey – for context, our previous visits in spring and winter 2019, yielded 28 and 22 species respectively.
In this part of the world we would expect inflated spring/summer counts as a suite of seasonal migrants visit southeastern Australia from northern Australia and beyond. We recorded a good number of such seasonal migrants, including Rufous Whistler, Sacred Kingfisher (at least two recorded and seemed to be a bit of courting behaviour going on), Black-faced Cuckoo-shrike (displaying interesting hovering behaviour over a patch of open grassland), and several cuckoos (Shining Bronze, Horsfield Bronze, Pallid and Fan-tailed). There were also inflated numbers of Yellow-faced Honeyeaters and Striated Pardalotes, which is typical for this time of year.
On the big dam were a decent number of ducks with a greater variety of species than usual. A calling and displaying male Musk Duck was a highlight. Other ducks included Chestnut Teal, Pacific Black Duck and Australian Wood Duck. Other water birds were observed in areas of inundated grassland and woodland, including White-faced Heron, Australian White Ibis, Sacred Ibis and Masked Lapwing. We watched in awe as a pair of Swamp Harriers worked back and forth over these low-lying areas, attracting plenty of attention from other species.
The growth in the planted vegetation has been fantastic to observe over the past few years and the structure of the vegetation is changing all the time with some patches becoming more dense as shrubby species grow and tree species regenerate, while other areas become more open as the canopy layer becomes more established. Importantly, resources like flowers and nectar are more available, attracting a diversity of honeyeaters. We were fortunate to observe Brown-headed, White-eared, White-naped, New Holland and Yellow-faced Honeyeaters foraging for nectar, as well as Red Wattlebirds and Silvereyes. Musk Lorikeets which also feed on nectar were present.
The small resident birds were in good number too, and many of these were recorded in the planted areas, including Brown, Buff-rumped and Striated Thornbills, Superb Fairy-wren, White-browed Scrubwren, Spotted and Striated Pardalotes and Grey Fantail. Several Grey Shrike-thrush were calling, pleasing all with their full repertoire of sounds. Australian Magpie, Grey Currawong, Little Raven and Crimson Rosella were common.
Other highlights to round out the visit included a pair of Wedge-tailed Eagles soaring low over the woodland and a Nankeen Kestrel hovering and foraging over grassland. It certainly was an exciting visit and the benefit of the biorich plantings is clearly showing, even beyond the number of species supported. There was plenty of bird breeding activity observed, evidence that a healthy ecosystem is in play!
By Grant Palmer
Autumn feast of flocking birds in May 2016 – 30 species in one day
Grant Palmer (on left) Phil Kinghorn and Louise Humble.
The autumn bird walk was greeted with sunny skies and pleasant conditions which quickly turned to overcast skies and gusting wind as the count started – which unfortunately meant a distinct lull in bird activity through the first section, just a few Australian Magpies and a distant calling Grey Shrike-thrush. The bird count started proper with a small flock of 6 Yellow-tailed Black Cockatoos flying lazily overhead, emitting their very distinctive calls as they headed into the Lal Lal State Forest.
Rounding the western edge of the first lot of revegetation, we were lucky enough to stumble upon a mixed species foraging flock, a typical phenomenon at this time of year in southern Australia. Mixed species foraging (MSF) flocks include a range of a nuclear and attendant species which take part to gain advantages such as increased foraging efficiency or reducing predation risk. By foraging in groups birds can take advantage of prey flushed by other individuals or avoid areas where food has already been depleted. By having more pairs of eyes, there is more chance of detecting potential predators also. The MSF we had the pleasure of observing included many Yellow-faced Honeyeaters and New Holland Honeyeaters, a White-eared Honeyeater, a few Brown-headed Honeyeaters and White-naped Honeyeaters and Silvereyes all working through flowering Swamp Gum in the planted section, with Brown Thornbills and Superb Fairywrens working the lowest levels, a Spotted Pardalote pipping in the foliage, and a Golden Whistler was also lurking in the inner foliage. A Grey Shrike-thrush and Grey Fantail were also clearly associating with this group. Watching this group of birds over a number of minutes provided a real highlight for the day.
The large dam supported unprecedented numbers of Australian Wood Duck – conservatively counted at 120-odd individuals – which were spread between the bank or on open water. Other waterbirds included several Pacific Black Duck, a lone Grey Teal, some Eurasian Coots, a pair of Hoary-headed Grebes and a lone Little Pied Cormorant. A pair of Masked Lapwing stood motionless on the shoreline, while a Swamp Harrier soared lazily overhead. A second pass of the dam later uncovered a dozen or so Australian Shelducks which had made their way on to the water.
The dreaded gorse on the western boundary housed a rare treat, a pair of Striated Fieldwrens, which kept close to the prickly cover as they foraged, making the most of a brief patch of sun. There was also a small flock of Red-browed Finch feeding on the ground in the vicinity. The swamp gums on the far side of the dam were a mass of Red Wattlebirds – their aggressive nature either driving other nectarivores out of the patch (most likely), or their constant harsh calling was drowning out all other calls. There was in excess of a hundred birds recorded in the patch. They were clearly making the most of the copious swamp gum flowers and nectar. There were also some Crimson Rosellas, mostly immatures, in this patch too.
The remnant patches of swamp gum in the back paddock produced good views of a pair of Eastern Rosellas, and a lone Noisy Miner (the miners are always present but in recent times numbers have always been very low). Striated Pardalotes were constantly calling from the canopy. Out in the more open areas, a few Australian Magpies moved around, while a Common Blackbird called from dense understorey along the boundary.
It wasn’t until we moved through the relatively large patch of remnant large old swamp gums on the eastern side that we observed the first laughing Kookaburra of the day. This patch was rather quiet as the now howling wind put a stopper on bird activity. Amongst gusts, a few striated Thornbills could be heard calling in the canopy.
All up, the bird species count was 30 species for the morning, with the MSF providing the highlight.
Rounding the western edge of the first lot of revegetation, we were lucky enough to stumble upon a mixed species foraging flock, a typical phenomenon at this time of year in southern Australia. Mixed species foraging (MSF) flocks include a range of a nuclear and attendant species which take part to gain advantages such as increased foraging efficiency or reducing predation risk. By foraging in groups birds can take advantage of prey flushed by other individuals or avoid areas where food has already been depleted. By having more pairs of eyes, there is more chance of detecting potential predators also. The MSF we had the pleasure of observing included many Yellow-faced Honeyeaters and New Holland Honeyeaters, a White-eared Honeyeater, a few Brown-headed Honeyeaters and White-naped Honeyeaters and Silvereyes all working through flowering Swamp Gum in the planted section, with Brown Thornbills and Superb Fairywrens working the lowest levels, a Spotted Pardalote pipping in the foliage, and a Golden Whistler was also lurking in the inner foliage. A Grey Shrike-thrush and Grey Fantail were also clearly associating with this group. Watching this group of birds over a number of minutes provided a real highlight for the day.
The large dam supported unprecedented numbers of Australian Wood Duck – conservatively counted at 120-odd individuals – which were spread between the bank or on open water. Other waterbirds included several Pacific Black Duck, a lone Grey Teal, some Eurasian Coots, a pair of Hoary-headed Grebes and a lone Little Pied Cormorant. A pair of Masked Lapwing stood motionless on the shoreline, while a Swamp Harrier soared lazily overhead. A second pass of the dam later uncovered a dozen or so Australian Shelducks which had made their way on to the water.
The dreaded gorse on the western boundary housed a rare treat, a pair of Striated Fieldwrens, which kept close to the prickly cover as they foraged, making the most of a brief patch of sun. There was also a small flock of Red-browed Finch feeding on the ground in the vicinity. The swamp gums on the far side of the dam were a mass of Red Wattlebirds – their aggressive nature either driving other nectarivores out of the patch (most likely), or their constant harsh calling was drowning out all other calls. There was in excess of a hundred birds recorded in the patch. They were clearly making the most of the copious swamp gum flowers and nectar. There were also some Crimson Rosellas, mostly immatures, in this patch too.
The remnant patches of swamp gum in the back paddock produced good views of a pair of Eastern Rosellas, and a lone Noisy Miner (the miners are always present but in recent times numbers have always been very low). Striated Pardalotes were constantly calling from the canopy. Out in the more open areas, a few Australian Magpies moved around, while a Common Blackbird called from dense understorey along the boundary.
It wasn’t until we moved through the relatively large patch of remnant large old swamp gums on the eastern side that we observed the first laughing Kookaburra of the day. This patch was rather quiet as the now howling wind put a stopper on bird activity. Amongst gusts, a few striated Thornbills could be heard calling in the canopy.
All up, the bird species count was 30 species for the morning, with the MSF providing the highlight.
Survey method used
Swampy paddock to the west of ImLalSouth.
The fixed route monitoring method, developed by BirdLife Australia, was selected by the bird survey leader Tanya Loos to measure the long term changes in bird diversity and numbers at the ImLal site. This method is particularly suitable for picking up location specific changes over time.
The fixed route monitoring method will allow us to say definitively in five or ten years whether or not the species diversity and numbers of birds have increased at the site overall since the outset of the project.
To keep it simple, and easy to replicate over a long period of time, we have kept the survey design to one long survey (two hours) that moves through the site at a steady pace and always along the same route, with the same stopping points, see pdf of the route map.
Participants have also expressed a desire to capture when we see the bush birds leave the swamp gum remnants that surround the plantation sites, and actually forage within the plantation. Habitat usage – such as observations of Yellow-faced Honeyeaters, and other birds such as Brown Thornbills foraging in plantation regrowth is difficult to assess statistically when we only have one small site. Statistically meaningful data relies upon the study design having many sites – ideally 30 to over 100, and with some control sites, and randomness in there as well.
Each of the two plantations is roughly 5ha, so a way around this problem could be to carry out a standard 5ha bird search on each planting, ignoring birds in the swamp gum remnants and focusing solely in the adjoining ‘paddocks.’ This could be done two to four times a year, and would be a way to capture the changes in habitat as the plantations grow, as well as use of the plantations by the local bird population.
The fixed route monitoring method will allow us to say definitively in five or ten years whether or not the species diversity and numbers of birds have increased at the site overall since the outset of the project.
To keep it simple, and easy to replicate over a long period of time, we have kept the survey design to one long survey (two hours) that moves through the site at a steady pace and always along the same route, with the same stopping points, see pdf of the route map.
Participants have also expressed a desire to capture when we see the bush birds leave the swamp gum remnants that surround the plantation sites, and actually forage within the plantation. Habitat usage – such as observations of Yellow-faced Honeyeaters, and other birds such as Brown Thornbills foraging in plantation regrowth is difficult to assess statistically when we only have one small site. Statistically meaningful data relies upon the study design having many sites – ideally 30 to over 100, and with some control sites, and randomness in there as well.
Each of the two plantations is roughly 5ha, so a way around this problem could be to carry out a standard 5ha bird search on each planting, ignoring birds in the swamp gum remnants and focusing solely in the adjoining ‘paddocks.’ This could be done two to four times a year, and would be a way to capture the changes in habitat as the plantations grow, as well as use of the plantations by the local bird population.
Species composition observed to date
White-eared Honeyeater. PHOTO:Julian Robinson
The most commonly observed species on site to date have been Australian Magpie, Crimson Rosella, Eastern Rosella, Grey Teal and the Noisy Miner, which have been observed at 7-8 surveys. A pdf of the Bird List species observed at the ImLal site as at 30 June 2013 is attached here.
The Grey Teal is part of our waterbirds contingent that may be observed on or near the two dams on the site – Australian Wood Duck, Chestnut Teal and Hardhead make up the duck species. White-faced Heron are regularly observed as well a single sighting of a Pacific Heron. Both species of Ibis also occur on site – largely due to the inundated paddock next door.
Australian Magpie is an open country bird. We could also put seed eaters such as Galah and Eastern Rosella in this group, and the aerial insectivore Welcome Swallow. Australasian Pipit, Yellow-rumped Thornbill, and Willie Wagtail are also typical species of the open country and it is no surprise to see them in the mix of paddock and remnant swamp gums at ImLal.
What is fascinating at the Imlal site is that although we saw Noisy Miners during all the surveys through to 2013, by the end of that year the Noisy Miner colony in the remnant at the centre of the biorich site seemed to have inexplicably vanished. In early surveys, we never saw more than 7-10 birds and we did not observe a total exclusion of other birds from the remnant patches in the middle and north of the site that the Miners occupy (see below for more on the Noisy Miner).
In these remnant patches, we regularly observe forest and woodland insectivores that are usually excluded by Miners – species such as Spotted and Striated Pardalote, Striated and Brown Thornbill, Grey Fantail and honeyeaters such as White-naped, White-eared and Yellow-faced Honeyeater.
The ImLal site is located on the border of the Victorian Volcanic Plain and the Central Victorian Uplands Bioregion and many of the species listed above, especially the White-eared Honeyeater, are associated with forests rather than woodlands. Other forest species such as Scarlet Robin, Pied Currawong and Yellow-tailed Black Cockatoo have also been observed at ImLal. Pictured is a White-eared Honeyeater Lichenostomus leucotis; a bird usually associated with forests, but seen regularly in the swamp gum woodland remnants.
One starling and a few blackbirds are the only exotic bird species have been observed at ImLal to date.
The Grey Teal is part of our waterbirds contingent that may be observed on or near the two dams on the site – Australian Wood Duck, Chestnut Teal and Hardhead make up the duck species. White-faced Heron are regularly observed as well a single sighting of a Pacific Heron. Both species of Ibis also occur on site – largely due to the inundated paddock next door.
Australian Magpie is an open country bird. We could also put seed eaters such as Galah and Eastern Rosella in this group, and the aerial insectivore Welcome Swallow. Australasian Pipit, Yellow-rumped Thornbill, and Willie Wagtail are also typical species of the open country and it is no surprise to see them in the mix of paddock and remnant swamp gums at ImLal.
What is fascinating at the Imlal site is that although we saw Noisy Miners during all the surveys through to 2013, by the end of that year the Noisy Miner colony in the remnant at the centre of the biorich site seemed to have inexplicably vanished. In early surveys, we never saw more than 7-10 birds and we did not observe a total exclusion of other birds from the remnant patches in the middle and north of the site that the Miners occupy (see below for more on the Noisy Miner).
In these remnant patches, we regularly observe forest and woodland insectivores that are usually excluded by Miners – species such as Spotted and Striated Pardalote, Striated and Brown Thornbill, Grey Fantail and honeyeaters such as White-naped, White-eared and Yellow-faced Honeyeater.
The ImLal site is located on the border of the Victorian Volcanic Plain and the Central Victorian Uplands Bioregion and many of the species listed above, especially the White-eared Honeyeater, are associated with forests rather than woodlands. Other forest species such as Scarlet Robin, Pied Currawong and Yellow-tailed Black Cockatoo have also been observed at ImLal. Pictured is a White-eared Honeyeater Lichenostomus leucotis; a bird usually associated with forests, but seen regularly in the swamp gum woodland remnants.
One starling and a few blackbirds are the only exotic bird species have been observed at ImLal to date.
The Noisy Miner in the remnants on the edges of the biorich plantation sites
The Noisy Miner and lerps they encourage, contributing to dieback. PHOTO:Geoff Park
The presence of the Noisy Miner on site presents an interesting problem. The Noisy Miner, Manorina melanocephala, is a hyper aggressive, colonial honeyeater associated with remnant woodlands. A native honeyeater, it should not to be confused with the introduced Indian or Common Myna.
Groups of Noisy Miners are known to exclude nearly all birds from the territory they occupy. Noisy Miners play a large part in contributing to poor eucalypt health and are often part of the process known as rural dieback through what is often described as psyllid 'farming.'
Lerps are sugary coated houses for tiny sap sucking insects called psyllids. Many birds relish this sugary coating, and eat the insect and the coating at the same time for a carbohydrate and protein packed meal. The Noisy Miners, however, carefully eat the coating and leave the insect behind. What’s more, they work very hard to exclude any birds from their territory that may harm the psyllids.
Psyllid farming benefits the Noisy Miners, but has a significantly negative impact on the health of the forest or woodland, as the psyllids and other insects are protected from their usual predators and so their populations can increase exponentially.
When Noisy Miners are removed from a patch (usually by shooting), small woodland birds such as Pardalotes and Thornbills will rapidly recolonise the Miner’s territory, sometimes within hours.
Groups of Noisy Miners are known to exclude nearly all birds from the territory they occupy. Noisy Miners play a large part in contributing to poor eucalypt health and are often part of the process known as rural dieback through what is often described as psyllid 'farming.'
Lerps are sugary coated houses for tiny sap sucking insects called psyllids. Many birds relish this sugary coating, and eat the insect and the coating at the same time for a carbohydrate and protein packed meal. The Noisy Miners, however, carefully eat the coating and leave the insect behind. What’s more, they work very hard to exclude any birds from their territory that may harm the psyllids.
Psyllid farming benefits the Noisy Miners, but has a significantly negative impact on the health of the forest or woodland, as the psyllids and other insects are protected from their usual predators and so their populations can increase exponentially.
When Noisy Miners are removed from a patch (usually by shooting), small woodland birds such as Pardalotes and Thornbills will rapidly recolonise the Miner’s territory, sometimes within hours.
Revegetation design can impede the spread of Noisy Miners
Striated Pardalote. From Aviceda.org
Revegetation design and remnant management may have significant impacts on the success and spread of Noisy Miner colonies. The challenge at ImLal is to ensure that that the establishment of the two plantations hinders rather than helps this notorious honeyeater – and that the monitoring program can capture this.
Steve Murphy’s careful observation and the onsite creation of the many layered structure of natural woodlands should ensure that the Noisy Miners are not advantaged. Like many of our smaller, insect eating bush birds, the Striated Pardalote, Pardalotus striatus, contributes significantly to Eucalypt health by eating sap sucking insects such as psyllids.
At ImLal, the colony appears to be very small, and restricted to the remnants in the north and middle of the site. Insectivore and other small bird exclusion appears not to be happening. Many questions are raised: to start with, these birds may occur in colonies of up to 200 individuals, but here at ImLal we have never seen more than 10 – why are the Noisy Miner numbers comparatively low? Do Noisy Miners occur in other sites nearby? Are they breeding? Is there a lot of aggression towards other birds occurring?
To date, we have observed just two incidences: one Noisy Miner chasing a Red Wattlebird, which is a large and aggressive honeyeater in its own right; and, secondly, a Noisy Miner chasing a Laughing Kookaburra. Are the low numbers of Noisy Miners because the bird community is more of a forest than a woodland bird community?
By 2014, the Noisy Miner colony in the remnant at the centre of the biorich site seemed to have disappeared. Whether this us temporary or not it's too early to be determined.
The questions raised by the establishment of the two biorich plantation sites are many. The careful management of Noisy Miners involves ensuring that revegetation sites discourage rather than encourage the colonies. This includes ensuring that there are not peninsulas and clumps of eucalypts protruding from the main remnant area, smoothing out any sharp edges, as well as the establishment of a structurally complex ground layer vegetation. The plantations have a mix of eucalypts, shrub and ground layer flora, and the natural regeneration sites presumably will have also this mix. The remnant swamp gum woodlands, where the Miners are present has been grazed by a herd of about a dozen cows, creating a habitat that is ideal for Noisy Miners. Will the Miners be discouraged from the remnants if we plant shrubs, such as Tree Violet, and a suite of wattle species in the remnants?
Researchers Dr Merilyn Grey and Professor Micheal Clarke from Latrobe University have compiled an excellent handout entitled The Noisy Miner: challenges in managing an overabundant species. They emphasise that, “There is no ‘one size fits all’ habitat restoration practice to deter Noisy Miners. Habitat restoration should be tailored to specific vegetation types, remnant sizes and remnant shapes to accommodate a wide range of animals, not just birds. An element of ‘learning by doing’ (adaptive management) must be involved.”
Where to from here?
New bird survey leader, Grant Palmer, (right) a research fellow at Federation University, with Tanya Loos on the 20th bird survey.
The ImLal site is known as a demonstration project – the challenge for us is to ensure that the type of data collected will:
1) Show that the bird species and numbers increase at the site over time (our original aim); and
2) Capture the data required to demonstrate that the plantations are not encouraging the Noisy Miners, so that we can make recommendations for those establishing similar projects in other Noisy Miner areas.
This is very much a preliminary report which raises more questions than it answers. The author will be enlisting the advice and assistance of a number of workers in the Noisy Miner/ Revegetation and Plantation field to check the survey methodology and design.
Stay tuned for the follow-up.
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