Grey-crowned Babbler project update 2014

With the recent, generous donation from Alcoa and Birdlife Melbourne to assist Friends of the Grey-crowned Babbler with their conservation efforts, it is timely to reflect on what has been achieved with regards to this species’ conservation in Victoria and what remains to be done.

It is now more than twenty years since Birds Australia initiated its Grey-crowned Babbler (babbler) conservation project in Victoria, thanks to a one-year grant from the Australian Government’s National Estate funding program. It is also twenty years since Birds Australia and other community organisations first applied for funding to do on-ground works to assist with the babblers’ survival. So how is this charismatic and sociable bird faring?

Grey-crowned Babbler, photograph by Chris Tzaros

Population trends

Overall, the babbler population in Victoria has declined by at least 90% over the past 150 years and has disappeared from more than 50% of its former range, so the species is still at a high risk of extinction. Collectively it is estimated that there are about 500-600 family groups persisting in Victoria, with key strongholds located around Violet Town, Euroa, Benalla, Rutherglen, Barmah, Boort and Kerang.  Even in these stronghold districts, though, there is a general downwards trend in total numbers and the size of each family group. During the lifetime of this project, moreover, family groups or populations have disappeared from some well-known former parts of their range, including the Mornington Peninsula, Maryborough, Castlemaine, Kiata, Nagambie and Rupanyup.

Importantly, however, in those districts where community groups and conservation agencies have focused their conservation efforts, there have generally been positive responses in terms of population size and breeding success. We know, therefore, that it is possible to help babblers – it is just a matter of having the resources and the time to do it.

Grey-crowned Babbler, photograph by Chris Tzaros

Fragmentation causes social disruption

The major cause of the babbler’s decline in Victoria has been the loss of their preferred woodland habitat. Over the past 150 years these woodlands have been largely cleared for agriculture, mining, urban development and firewood collection. As a consequence, babbler populations have shrunk in size and become isolated from each other. The number of birds in each family group has also declined, because smaller populations of babblers produce fewer young. For this highly social species, therefore, habitat fragmentation has caused major social disruption.

Given this understanding of the threats to the babbler, the Friends of the Grey-crowned Babbler and other community groups have focused their efforts on three main conservation actions:

1. increase the total amount of habitat available for babblers in priority areas by encouraging the protection and restoration of habitat on private and public land
2. increase the quality and availability of habitat at known babbler sites to increase group size and breeding success, and
3. increase the connectivity between isolated groups or patches of habitat. This creates more opportunities for birds to disperse and colonise.

Grey-crowned Babbler, photograph by Chris Tzaros

Achievements to date

One of the stand-out demonstrations of the success of this approach to the babbler’s conservation has been in the Lurg district, northeast of Benalla. Here, the local landcare group, Regent Honeyeater Project group, BirdLife Australia and many other groups and individuals have steadily protected and restored habitat and habitat corridors since the early 1990s. Over that time, a total of more than 1 000 hectares of habitat has been protected and restored, comprising more than 200 sites and involving more than 90% of local landholders. When monitoring of babbler numbers began in 2001, the babbler population here was estimated to comprise 13 groups and 53 birds.  Now the population has increased to 21 groups and 106 birds, with average family size increasing from four birds to five.

In the Euroa-Violet Town districts, where Friends of the Grey-crowned Babbler have targeted most of their on-ground conservation efforts, the responses by babblers to more, improved habitat has not been as dramatic as at Lurg but nonetheless positive. In 2009, with funding support from the Norman Wettenhall Foundation and the Goulburn Broken CMA, researchers from the University of Melbourne and Trust for Nature compared babbler populations at sites where landholders had protected habitat compared with sites where there was no habitat improvement. Their study showed that babbler groups were more likely to have persisted at sites where there had been habitat works, breeding success was higher at sites with additional habitat and the number of young raised per family at sites with additional habitat was nearly double that of babbler families at sites with no additional habitat.

Based on these findings, Friends of the Grey-crowned Babbler continue to implement or support the implementation of their key conservation actions for babblers across these districts. Since the project began, twenty years ago, the Friends group, working with local landcare groups, conservation agencies and Trust for Nature has protected and restored more than 2 000 ha of habitat through the Euroa-Violet Town districts.

The Group’s conservation mantra is plan big, based on good science, and then try to save the species one family at a time.  The recent grant from BirdLife Melbourne will help support the group continue with delivering these aims and the Friends group gratefully acknowledges the support of BirdLife Melbourne and Alcoa for its work.

Contributor: Doug Robinson, Trust for Nature