The forest birds of Australia include vibrant parrots, darting honeyeaters, vivid blue fairywrens, and the unassuming “little brown birds.” Some can be found in urban gardens, including rosellas, laughing kookaburras, and willie wagtails. Others, like quick parrots and regent honeyeaters, are extremely rare and need bird aficionados to search for them for days or even weeks.
Other woodland birds like pardalotes, thornbills, treecreepers, gerygones, and nightjars may have escaped your notice. There are 40 species of forest birds that are categorized as threatened, and several more are in decline.
And just this month another six woodland birds were added to the national threatened list.
Efforts to help these species recover are being made. Tree replanting and nest box installation are frequent tasks. But it’s critical that we understand which initiatives are having the biggest impact. By allocating resources to the most effective interventions, we may then be certain that we are doing enough to recover these birds.
All the published research that examined the efficiency of 26 conservation measures for woodland bird communities was compiled in our systematic review. However, we were unable to find much support for the effectiveness of the majority of these actions.
Why don’t we know more about what works?
Australian woodland birds are a well-studied group of species. However, there is a dearth of research on the effectiveness of management for this ecological community. This restricts our capacity to produce broad, fact-based recommendations.
Some actions are certainly beneficial. For example, we know replanting trees and shrubs helps recover woodland birds. Large chunks of dead wood left on the ground are beneficial to birds like robins and treecreepers as well.
Many of the studies we looked at, however, did not compare “control” sites i.e., areas that were otherwise similar to the intervention sites with the intervention sites. That made evaluating the efficacy of various actions challenging. Because of this, we are unable to determine which acts and how much of an impact they will have in certain situations.
Surprisingly few interventions had been the focus of studies using control sites, when birds were observed in environments with no interventions. This was true even for common actions, like control of weeds, feral herbivores (goats, pigs, deer) and predators (cats and foxes), or nest box installation.
All these actions probably have at least some benefits. However, we are unable to estimate the size of the benefits or identify the particular action that has the greatest impact without additional research and appropriate controls.
Where the evidence exists, results are mixed
Interestingly, four actions for which we could collate some clear evidence had mixed results. These measures included grazing control, controlled burning, noise miner control, and habitat preservation. Evidence suggests that the site and management environment affect their effects on birds.
Reducing livestock grazing had mixed results for woodland birds. There were times when it had no effects, times when it had negative impacts, and occasions when it had both.
It was doubtful that prescribed burning would increase the population of woodland birds because some studies found no effect and others found detrimental consequences.
These contradicting findings may be the consequence of variations in the bird communities, the seriousness of the threats, or variations in the ecological or climatic conditions of the study locations, as well as in the surrounding landscapes.
They could also be explained by differences in how the management actions were implemented (such as intensity, frequency, method) and monitored (for example, time since the action took place). But because there was only a handful of studies, we couldn’t tease apart these reasons.
We were unable to draw broad conclusions regarding the overall efficacy of 26 conservation activities for Australian woodland birds despite reductions in these species and continuous expenditure in their conservation. We still don’t know which management actions are most effective for this well-loved bird community. This knowledge gap is likely to be worse for less-studied taxonomic groups.
So what can we do to fill in the gaps?
To give us concrete answers, there are two key messages for conservation practitioners and researchers.
First, we must conduct more study aimed at evaluating the efficacy of management decisions and comprehending the context in which various outcomes occur. These investigations require meticulous statistical reporting, proper controls, and rigorous study designs.
Second, we urge practitioners to access the online repository of already-published studies that we did compile as well as the supplementary annotated bibliography. These offer an abundance of thorough, useful information about each management action. These materials are a thorough compilation of the best research that is currently available to support management choices for woodland birds.
We also support practitioner-researcher partnerships in order to assess management practices that are currently being used or that will be put to the test in the near future.
Unfortunately, these conclusions of “we need more research” and “it depends on the context” are not novel. However, we now have a clear understanding of the knowledge gaps.
In the meanwhile, the most important thing we can do is to avert habitat destruction and loss in the first place.
