Fairy-wren study

The presence, absence and patterns of diversity and abundance of birds can yield a great deal of information about the status of habitats, helping to evaluate management practices, determine plot viability and monitor bush regeneration projects. By understanding the behaviour of birds, we can adjust environmental management practices to return remnant bush to its appropriate, balanced carrying capacity for all species which reside in it.  For instance the presence or absence of particular bark foraging species can inform us about the viability of plot sizes and the balance of some thornbill species can inform us about the plot size viability and vegetation structure. The outcome can be a community which enjoys healthy, viable natural surroundings, boosting the quality of life for everyone.

2007 Northern Beaches Fairy-wren Survey

In 2007, in conjunction with Pittwater and Warringah Councils, I organised a systematic community survey of 6 bush remnant patches on the Sydney Northern Beaches. The primary goal of the survey was to understand the patterns of distribution of the two resident fairy-wren species in the locality: the Variegated Fairy-wren Malurus lamberti and the Superb Fairy-wren M. cyaneus. Traditional wisdom on the habitat “preferences” of these two species has been less than reliable and, as a long term bird watching guide I have found myself caught out on the presence or absence of these species on a number of embarrassing occasions!

Our method was to have groups of 3 or 4, led by an experienced bird watcher. Survey trails were marked on a map of each reserve and when a family of fairy-wrens was observed that family was marked on the trail map by a number. The number was entered onto another sheet which recorded the species type and number of family members observed. I conducted a pre-survey presentation night on the Thursday before the survey, so that everyone knew what to expect and was revved up for a great weekend of birding!

The survey was a great success in that good numbers of fairy-wrens were recorded on all reserve trails, many people who did not normally enjoy the reserves of the locality learned to appreciate their values more fully and I obtained a great deal of data which would help for future comparison surveys. However, the biggest surprise came when I superimposed vegetation communities over the trail maps . . .

Survey outcomes . . . something unexpected

At first the presence of the two species did not make any sense. Traditional wisdom is that Superb Fairy-wrens are found in sparse vegetation and Variegated Fairy-wrens are found in dense vegetation . . . sometimes. What I found when I examined the vegetation patterns was that Superb Fairy-wrens were found in sparse vegetation, dense vegetation, wet vegetation and dry vegetation. I found the same for Variegated Fairy-wrens. However, a pattern soon emerged which had been overlooked in the past: Superb Fairy-wrens were found only in monocultures, degraded vegetation and vegetation communities which were generally low in diversity, regardless of density, sparsity, wetness or dryness. On the other hand, Variegated Fairy-wrens were found in diverse vegetation communities and generally those with minimal disturbance, regardless of density, sparsity, wetness or dryness. This was something new: information which, if confirmed and further studied, could serve as a valuable indicator of the condition of habitats in urban environments.

Commencing the study

The first step in learning how to use this knowledge is to understand why. How is the behaviour, physiology and perhaps social needs of these superficially similar birds shaped so that they live in such different habitats? This is the quest for my current research project. The study will involve researching the lives and behaviour of both species, along with careful examination of their morphology. I will do the same with a number of species in the same foraging guilds which share habitat with these species and at least one species, i.e. the White-browed Scrubwren Sericornis frontalis, which shares both habitat types. I hope to publish within three years.