Bird species numbers act as an indicator of biodiversity richness
By Tanya Loos
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.
On our October 2011 survey, we observed birds using the young plants in the South ImLal site for the first time. The Yellow-faced Honeyeater, Lichenostomus chrysops, is a common honeyeater in the area, and 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. This is the first bird species observed to benefit directly from the project volunteers’ hard work thus far!
On our October 2011 survey, we observed birds using the young plants in the South ImLal site for the first time. The Yellow-faced Honeyeater, Lichenostomus chrysops, is a common honeyeater in the area, and 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. This is the first bird species observed to benefit directly from the project volunteers’ hard work thus far!
Survey method used
Swampy paddock to the west of ImLalSouth.
The fixed route monitoring method, developed by Birds 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
Fifteen surveys have been carried out on site, and a total of 70 species have been observed.
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 February 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 have seen Noisy Miners during all eight surveys, there are never more than 7-10 birds sighted and we have not observed 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 one blackbird are the only exotic bird species have been observed at ImLal to date.
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 February 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 have seen Noisy Miners during all eight surveys, there are never more than 7-10 birds sighted and we have not observed 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 one blackbird 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 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?
The questions raised by the establishment of the two biorich plantation sites are also 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?
Where to from here?
Looking north towards remnant dominated by Noisy Miners.
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.”
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.
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.
- If you wish to join us on one of our monthly or bimonthly bird surveys, contact Tanya Loos at nature@wideband.net.au or send an email to Gib Wettenhall through the Contact menu.
