The charisma of the Willie Wagtail (Rhipidura leucophrys) is difficult to describe to the unknowing. A bird much bolder than its size would suggest, the Wagtail is one of Australia’s most widespread bird species. As such, the sight of a Wagtail’s characteristic restless swaying – moves not misplaced at an 80’s disco – is commonplace to most Australians owning a backyard. It was my job to follow this species for two weeks with a GPS logger, watching it dip and dive its way through the woodlands of southern NSW. Aside from tracking the Willie Wagtail in its cheerful forays, I also followed the activities of the Superb Fairy-wren (Malurus cyaneus), opened a lot of farm gates, and enjoyed many a country bakery during my voluntary duties. Watching birds, following birds, thinking like a bird, for day upon day, with just the trees and the birds.
I spent the term break volunteering under ANU PhD candidate Donna Belder, who is into her 2nd year of research into the effect of restoration plantings on woodland bird species. Located within the Southwest Slopes bioregion, which comprises a large area of southern NSW, Donna’s project addresses key themes in biodiversity conservation and habitat restoration.
The aim of Donna’s research is to determine whether restoration plantings in an agricultural setting are sustaining populations of endemic woodland bird species. The principle of her research method is to compare various measurements and observations at remnant woodland patches, to revegetated areas of various shapes and sizes. However, her research methods are unique in that they follow the movements and activities of individual birds, rather than relying on basic survey presence/absence data. Individual nests are monitored over the breeding season, often with the use of camera traps, in order to paint a picture of nesting success. Furthermore, individual birds within various sites are banded with identifying colour bands on their legs. This enables an indication of whether individual birds are remaining at the same site, or moving across habitat patches in order to find sites of better habitat quality.
It takes a skilled eye to distinguish a blue band from a green band on a Fairy-wren’s foot, as it leaps across dense thickets of Acacia. That is why I was assigned the slightly easier task of following individual Willie Wagtails and Superb Fairy-wrens with a GPS in order to map their home ranges. This usually involved watching and listening to an individual bird, recording the bird’s activities and the substrates it lands on, and then getting the coordinates for these points. An accurate representation of an individual bird’s territory usually requires over a hundred data points, which takes anywhere from 1.5-3 hours. By mapping the size and distribution of these territories, this component of Donna’s research hopes to provide an indication of the concentration and distribution of habitat resources across remnant woodlands and restoration plantings.
Donna’s PhD project seeks to fill an important void of knowledge in biodiversity conservation. Habitat loss represents the most significant threat to biodiversity in Australia, with agricultural landscapes responsible for a substantial claim of Australia’s biodiversity loss (Montague-Drake et al, 2009). Once dominated by box-gum grassy woodlands, remnant patches of native vegetation in the South-west Slopes are small and isolated (Gibbons and Boak, 2002), leading to considerable recent efforts to revegetate parts of the landscape (Montague-Drake et al, 2009). However, the efficacy of these plantings for biodiversity conservation requires ongoing research and monitoring.
Established in 2000 and led by Professor David Lindenmayer at the ANU, the long-term South West Slopes Restoration Study aims to examine faunal responses to revegetation efforts in an agricultural matrix. Previous research by Lindenmayer et al (2010) suggests that the effect of restoration plantings on bird species can be understood through three main characteristics of the planting – context, configuration and content.
The importance of landscape context for woodland birds is well known, with bird species richness found to be strongly correlated to the characteristics of the area surrounding plantings (Montague-Drake et al, 2009; Lindenmayer et al, 2010). This reinforces the notion that the matrix matters, with native vegetation providing additional habitat for bird species and facilitating movement between patches (Lindenmayer et al, 2010). Upon watching several Wagtails dive between isolated paddock trees on their forages outside restoration plantings, this much is clear. The same can be said for many species that likewise use paddock trees as stepping stones in a matrix largely devoid of shelter or habitat resources.
Whilst the voids of a fragmented landscape can be partially filled by native vegetation, the issue of edge effects remain, with the increased edge effect characteristic of small or linear plantings shown to correlate to a decline in woodland birds (Montague-Drake et al, 2009). In visiting a variety of planting configurations, this decline in species richness was obvious, and there was a greater tendency for birds such as the Willie Wagtail to perch and forage outside patch boundaries.
Finally, the actual content of restoration plantings bears a large influence on bird occupancy. Lindenmayer et al (2010) found that key habitat variables supporting woodland birds include the presence of fallen logs, mistletoe, understorey and mid-storey. In drawing on the observed habits of the Superb Fairy-wren, there is a notable preference for this species to nest, perch and forage in a dense mid-storey and understorey. Similarly, fallen logs provide a great place for a Wagtail to forage in search of insects that inhabit these structural components.
It is difficult to make sweeping land management recommendations at this stage of Donna’s research, but the implications of this research for the conservation of woodland birds are significant. With an increasing impetus to revegetate parts of the Australian agricultural landscape, directing these efforts towards methods that will maximise the return for biodiversity conservation is a big step forward in a country rapidly losing its unique flora and fauna.
A final word of thank you to PhD candidate Donna Belder for sharing her knowledge and letting me tag along on her fieldwork adventures.
Gibbons, P., Boak, M., 2002. The value of paddock trees for regional conservation in an agricultural landscape. Ecological Management and Restoration 3(3): 205-210.
Lindenmayer, D. B., Knight, E. J., Crane, M. J., Montague-Drake, R. M., Michael, D. R., MacGregor, C. I., 2010. What makes an effective restoration planting for woodland birds? Biological Conservation 143: 289-301.
Montague-Drake, R. M., Lindenmayer, D. B., Cunningham, R. B., 2009. Factors affecting site occupancy by woodland bird species of conservation concern. Biological Conservation 142: 2896-2903.