Wednesday, 2 March 2022
This story originally ran in our March 2022 issue. To receive our Australian BirdLife magazine, become a member today.
Swift Parrots lead extraordinary lives which begin in their summer breeding grounds in the tall, old-growth forests of coastal Tasmania. Each autumn, they migrate northward across the sometimes treacherous waters of Bass Strait to overwinter on mainland Australia. Once there, they spend the cooler months scouring their vast south-eastern mainland range—from western Victoria to south-east Queensland—for fluctuating food resources. Typically, by late October/early November, the vast majority of the population have returned to Tasmania where they will spend the summer before embarking on their remarkable annual cycle all over again.
In 2009, BirdLife Australia took on the role of coordinating the biannual mainland monitoring for the Swift Parrot and Regent Honeyeater—programs that had first commenced back in the mid-1990s.
Monitoring two species with wild populations estimated to each be in the mere hundreds over such an enormous area of potential habitat is quite an undertaking—and at times the enterprise is wholly reliant on the contributions of many skilled and dedicated volunteer birdwatchers.
The job becomes even more complex when you consider that the primary food sources that determine habitat suitability—namely lerp, and the nectar from particular eucalypt species—have an availability that is highly variable both geographically and temporally during the non-breeding season, and which fluctuate in response to a range of factors such as natural cycles and weather conditions. Thus, Swift Parrot distribution and movement patterns on the mainland alter dramatically from year to year, and even within years, in response to resource availability, and are currently very difficult to predict in advance with any accuracy or confidence.
Together with the Regent Honeyeater, the Swift Parrot has long been the face of woodland bird conservation in south-eastern Australia, with these two Critically Endangered species in the hearts and minds of birders and conservationists right across the country. Complementing the specialised monitoring undertaken by ANU researchers across the Swift Parrots’ Tasmanian breeding range, over 25 years of searches undertaken by passionate citizen scientists have provided the National Swift Parrot Recovery Team and other researchers with invaluable information about how, when, and where Swift Parrots have used mainland habitats during the 1990s and 2000s. These observations have helped us to understand key ecological aspects of the species, including regular feeding areas, the relative importance of particular foraging resources, and trends in the way that they used the landscape.
A review of the past decades’ sightings, however, has alerted us to an apparent shift in the way that Swift Parrots utilise ‘traditional’ or ‘stronghold’ habitats, areas that have historically supported a significant proportion of the wild population during most years on the mainland. One such stronghold, the box-ironbark forests in central western Victoria, have been used far less by the species in recent times, and are now used only occasionally by large-sized flocks. In some years, these sites are barely visited by Swift Parrots at all. Conversely, anecdotal evidence suggests that the species is becoming more prevalent elsewhere on the mainland, such as the forests along the south-coast of New South Wales, which include many areas subjected to ongoing logging impacts. This departure from normal trends in habitat use signals that changes are occurring on the ground for Swifties on the mainland, which we suspect is in response to the growing influence of climate change on the patterns of eucalypt flowering, nectar flow, and lerp availability.
The current knowledge gaps around Swift Parrot ecology and habitat availability on the mainland is a significant constraint on the ability of BirdLife, the national recovery team, and relevant land managers to protect priority habitats, address threats, and implement other conservation actions. With the Swift Parrot currently closer to extinction than ever before, it’s urgent that we move quickly.
While the previous monitoring approach was invaluable at telling us where Swift Parrots occurred, it did not consistently capture other important information such as where they were not being found, the availability of various foraging resources at a given location, or the scale of survey effort applied at monitoring sites. To be able to identify precisely what mechanisms are driving this apparent change in the way that Swift Parrots are using mainland habitats, we needed to adapt our survey techniques to capture additional detailed data for all sites where searches have been undertaken, including measurements of foraging resources and the occurrence of other woodland birds. We were confident that this could be achieved using a simple and intuitive approach via BirdLife Australia’s widely used Birdata system.
For rare and highly mobile species, monitoring approaches that prioritise sampling intensity and maximise spatial coverage greatly enhance our ability to detect distribution patterns at multiple scales. In the late 2000s, the ANU developed a rapid-monitoring program across the Tasmanian breeding range of the Swift Parrot, in which 5-minute, 200-metre radius point counts are undertaken twice each season at a number of sites in key habitats. This approach has been instrumental in unpacking patterns of habitat use during the breeding season, producing more robust population estimates, and complementing other important research on the species regarding the impacts of predation by Krefft’s Glider (formerly Sugar Glider) on breeding birds.
Following the success of this monitoring method, in 2015 the approach was redesigned slightly for monitoring Regent Honeyeaters during the breeding season. For these surveys, a 5-minute, 50-metre radius survey method was applied to a large number of permanent sites within known and potentially suitable habitats, with each site visited twice per season. The short survey duration still allows for a high level of detectability of Regent Honeyeaters, while minimising the amount of time spent at each site and allowing the observers to visit a greater number of sites each day. The 5-minute, 50-metre radius survey method thus became the ongoing standardised survey method used by BirdLife Australia and ANU researchers in the National Regent Honeyeater Monitoring Program.
Given the simplicity of this survey method and its capability to capture data on other key environmental factors, it was decided that this method be applied to the refined Swift Parrot monitoring program.
Put simply, the revised Swift Parrot Search survey method involves a birdwatcher undertaking a 5-minute point count—primarily for Swift Parrots, but also seeking and recording counts for Regent Honeyeaters and all other bird species.
These surveys are undertaken while standing at the centre-point of a permanent, circular, 50-metre radius area on public land known to either support Swift Parrots historically, contain preferred habitat for the species, or be within potential habitat determined by a mix of computer modelling and expert knowledge of their habitat requirements. Within this same 50-metre radius search area, birdwatchers are also asked to estimate the intensity of flowering of each eucalypt and mistletoe species within that search area, and the presence of accessible freshwater. In using this method, we will be undertaking one of the first attempts ever in Australia to map flowering patterns over time at a range-wide scale. In 2022, we will also be asking birdwatchers to indicate whether lerp or flowering Golden Wattle, two other food sources used to varying extents by Swift Parrots, are present at each site.
In late April 2021, Swift Parrot Search was officially launched and more than 1,200 survey sites across Victoria, New South Wales, ACT and Queensland were made available to our supporters via Birdata and our project website. More than 500 further sites were added in mid-July. The establishment and roll-out of further permanent Swift Parrot Search monitoring sites has been an ongoing task for both BirdLife Australia and ANU staff since work began in 2019, with COVID-19 restrictions playing havoc with our on-ground field assessments. Once this initial major phase of site establishment is complete, it’s expected that there will be more than 3,000 sites distributed across south-eastern Australia—all aimed at collecting valuable information on Swift Parrots, Regent Honeyeaters and other threatened and declining woodland birds.
Despite the setbacks experienced at various stages of 2021, the performance of the program exceeded our expectations in its inaugural year. Overall, there were 1,739 surveys completed across 1,020 unique sites from 24 April through to 31 October, with Swift Parrots detected in 58 (3.3 per cent) of these surveys. There were more than 190 other bird species recorded at least once during these surveys, including many species listed as threatened at the state or national level such as Grey-crowned Babbler, Hooded Robin and Superb Parrot. Further, one of the most encouraging results to come out of 2021 was that 90 per cent of all surveys were accompanied by measures of flowering intensity. This is an excellent result when considering that this element of the revised method is entirely new for our volunteers, and will form the foundation for some exciting analysis in coming years.
With the method developed and most survey sites established, our primary goal now is to support volunteer birdwatchers and our amazing team of regional coordinators so that every site is surveyed at least once during each of the biannual 6-week survey periods—centred around the traditional third weekend in May and first weekend in August (see ‘Around the Grounds’ for details on surveys in 2022). Of course, surveys and general searches outside of these biannual periods are also highly valuable and welcomed, particularly during the times when Swift Parrots are likely to be on the mainland (approximately mid-March to mid-October). This data can assist us with filling the gaps of nectar availability trends and bird occurrence within a given locality or region.
In essence, the objective of this revised program is to help prevent the extinction of the Swift Parrot by addressing critical knowledge gaps. Through harnessing the immense collective power of hundreds of citizen scientists capturing robust data regularly and consistently, we’ll be able to understand the variability of Swift Parrot food sources at all scales over space and time across south-eastern mainland Australia, and the extent to which climate change influences this. In turn, this will increase our capacity to predict the occurrence of productive foraging resources ahead of time, allowing conservation actions to become more targeted.
But the benefits of this program will also extend beyond Swift Parrots. The novel approach of documenting flowering events will serve many other declining nectivorous species such as the Regent Honeyeater and the mistletoe-specialist Painted Honeyeater. Moreover, the broad application of this standardised 5-minute, 50-metre radius survey method may also help detect declines earlier among other woodland bird species which co-occur within Swift Parrot habitat on the mainland.
Although in its early stages, the future of this fledgling monitoring program is looking bright. The strength and quality of the data gathered by our determined volunteers will only grow over time, and in turn, provide us with the clarity needed for conservation actions to remain effective and up to date. Once we fill these key knowledge gaps around how Swifties use their winter mainland range, we can better protect key habitat areas, identify new areas needing attention, and help ensure a viable and secure future for the species.
Swift Parrot Search is a collaboration between BirdLife Australia and the Australian National University.
This story originally ran in our March 2022 issue. To receive our Australian BirdLife magazine,become a member today.
Swift Parrots are one of the only parrots in the world that migrates every year, making the long journey from Tasmania to mainland Australia in search of flowering gum trees. Yet, bushfires and continued native forest logging threaten this incredible bird's existence.
The Critically Endangered Swift Parrot is mostly bright green, with a dark-blue patch on the crown. Breeds in Tasmania and migrates to the mainland for winter.
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