Protecting the breeding population of Swift Parrots

The Swift Parrot (Lathamus discolor) is one of only two migratory parrots that fly from mainland Australia to breed in Tasmania. Arriving around springtime, they seek out our flowering blue gums, form mating pairs and spend their summer breeding and raising chicks. While they often reuse the same nesting sites, they don’t always turn up at the same site over successive years and this unpredictability can pose challenges when it comes to conservation efforts.

Swift Parrots are classified as Critically Endangered, and it is believed there are fewer than 1,000 breeding pairs remaining. There are a few reasons for their continued decline – including habitat loss, competition for nesting sites and predation of chicks and eggs. One of the biggest challenges they face comes from a seemingly innocuous cute and fluffy culprit; the sugar glider. Despite their name, sugar gliders, introduced to Tasmania in the 1800s, aren’t just a sweet tooth and dine on a range of foods – including eggs, insects, lizards and small birds. Their impact on Swift Parrot populations in Tasmania has been devastating. In fact, it’s estimated that nearly 85% of the Swift Parrot population is at risk each season of being killed by sugar gliders. Sugar gliders eat swift parrot eggs, chicks and even adult birds, drastically decreasing the reproductive success of the species. Research has shown that sugar gliders can impact up to 79% of nests, and 65% of breeding females in Tasmania can fall victim to sugar gliders each year. Sugar gliders are the only predators able to access breeding Swift Parrot nests due to very specific nest dimensions.

NRM South is embarking on a project to protect the breeding population of Swift Parrots and, over the next three and a half years will be working with DPIPWE, Australian National University (ANU), the Tasmanian Land Conservancy (TLC) and Conservation Landholders Tasmania on solutions to improve the species’ rates of breeding success. This ‘Protecting the breeding population of Swift Parrots’ project is part of a Regional Land Partnership – a component of the National Landcare Program, funded by the Australian Government.

The project will be focusing on how to protect Swift Parrots from sugar gliders, as well as working towards protecting and improving key habitat areas. Through an initial pilot project, researchers will be investigating whether localised sugar glider control has an effect on egg predation. The outcomes of this study will inform the best strategies for a longer-term control project. Previous research has shown that Swift Parrots will readily use artificial nest boxes for breeding so additional boxes will be installed at breeding sites where nesting sites are limited. Finally, measures will be put in place to protect high-value functional breeding habitat in important Swift Parrot breeding areas on private property through conservation covenants, and their associated natural values management plans.

IMPLEMENTATION

Swift Parrot nesting locations are highly variable across the landscape, and from year to year, which in turn influences the impact that project activities will have each year – and the overall likelihood of positive conservation outcomes for Swift Parrots in the short, medium and long term. This variability will be addressed through an adaptive management approach; regularly evaluating outcomes and modifying delivery mechanisms to suit. A pre-emptive approach (developed by researchers from the ANU’s Difficult Bird Research Group (DBRG)) to predict the breeding locations of swift parrots each year involves annual eucalyptus flower bud surveys in the lead-up to the breeding season, which will in turn inform management actions for that breeding season.

The delivery of on-ground activities will be managed internally by NRM South. The project incorporates three direct actions and two supporting actions:

DIRECT ACTION 1

Emergency interventions to prevent extinctions through trapping and euthanising sugar gliders, undertaken in years when nesting on mainland Tasmania is indicated.

Predator control activities will vary in location and scale and will be undertaken at Swift Parrot breeding sites throughout the breeding season. This management intervention is based on the (as yet untested) assumption that localised sugar glider control will reduce predation rates on breeding females, eggs and chicks and will therefore improve their breeding success and survival. A control pilot study will test this assumption and ANU will provide a report on the outcome of the pilot. If initial results are inconclusive, further work may be required to test the effectiveness of various sugar glider suppression methods.

DIRECT ACTION 2

Habitat augmentation by providing additional nesting resources (artificial nest boxes) in locations where breeding is limited by insufficient suitable nesting sites.

This is particularly important when Swift Parrots nest congregate in a restricted area. When food resources are less available across their breeding range, Swift Parrots tend to aggregate at localised sites, and in these situations it is predicted that existing nesting sites (includes natural and artificial nests) will have over 70% occupancy. The DBRG has already put substantial effort into developing and refining nest box designs tailored to suit Swift Parrots. The success of this approach would be measured using the number of nest boxes used for a breeding attempt by a Swift Parrot.

DIRECT ACTION 3

Establishing conservation covenants to protect high-value functional habitat on private property in perpetuity.

High-value functional habitat is defined as mature eucalypt forest that provides natural nesting sites suitable for Swift Parrots (tree hollows with an entrance hole diameter of ~5cm, a depth of ~15 cm and a height of ~40 cm) within foraging range (~5km) of a food resource (Tasmanian blue gum [E. globulus] and/or black gum [E. ovata]).

Four conservation covenants will be established over the course of the project. In depth spatial analysis to identify areas of high-value functional habitat on private land will be conducted as a project initiation activity. Covenants will be established through the DPIPWE’s Private Land Conservation Program (PLCP). The PLCP provides a coordinated, targeted and rigorous approach to the establishment of voluntary conservation covenants with private landowners. The TLC will be sub-contracted to establish management plans associated with each covenant and to deliver stewardship throughout the life of the project.

SUPPORTING ACTION 1

Identifying site locations through pre-emptive eucalyptus flower bud surveys.

This predictive approach will identify annually specific breeding site locations and inform decisions on which activities to undertake in each breeding season. This approach facilitates the adaptive management approach required for work with this species and addresses a key difficulty in delivering effective conservation services for a cryptic migratory nomadic species such as the Swift Parrot. Flower bud surveys of Eucalyptus globulus will be done in the month leading up to the foirst arrivals of Swift Parrots  and will involve multiple site visits to multiple indicator sites and, once birds have begun to nest, also includes bird surveys.

GIS based spatial analysis, combined with ground truthing of potential sites, will be used to identify areas of high-value functional Swift Parrot habitat on private land that are suitable for the establishment of conservation covenants.

SUPPORTING ACTION 2

Community (stakeholder) engagement and awareness raising activities will be conducted in key regional communities in southern Tasmania

These activities will highlight the key threats to the species and how they are being addressed by this project, including the requirement for and approach to sugar glider control and the importance of retaining foraging and nesting habitat. The community engagement approach will include events such as guided bird walks, community forums and cultural exchange field events in the Glamorgan Spring Bay, Tasman, Kingborough and Huon Valley municipalities. Key messaging will include the value of tree hollows to hollow-dependant species, the need to protect Swift Parrot habitat, the introduced status of sugar gliders and the negative impacts of sugar gliders on Swift Parrots, the need to control sugar gliders and guidance on minimising impact on important habitat when harvesting firewood.

Increasing stakeholder awareness surrounding sugar glider control will contribute to the management of potential public backlash related to the suppression of a ‘charismatic’ species that is native to Australia but introduced to Tasmania. Initial public response to the Sugar glider suppression trial, implemented by NRM South in 2019, indicate the Tasmanian public are mostly understanding and supportive of sugar glider control aimed at conserving Swift Parrots.

Education targeting land managers in key Swift Parrot breeding locations will focus on the importance of foraging habitat (E. globulus and E. ovata dominant vegetation communities) and nesting habitat (hollow bearing trees and mature trees likely to develop hollows). The approach will include the dissemination of printed information related to firewood harvesting and hollow bearing trees. This messaging will include information on how to retain nesting habitat when harvesting trees, including for firewood.