Birds of the Midlands – changes in land-use affect bird populations Journal article summary by Sue Jones Right across the world, bird habitat is being lost as more land is cleared for agriculture. Birds are also impacted by changes in farm management such as increased use of pesticides. In the Tasmanian Midlands, an important agricultural region, less than 10% of the original native woodland still remains, and restoration managers are keen to understand the best approach to restoring some woodland habitat. Glen Bain of the University of Tasmania and his co-workers have been investigating how bird populations have changed in the Midlands over the last 20 years. They were particularly interested to see how bird communities varied according to the environmental characteristics of the site. They surveyed birds at 72 sites across the Midlands, including woodland remnants, native grasslands, pasture and areas dominated by gorse. To look at changes over time, they compared their results with a similar survey carried out in 1996-98. They found that sites surrounded by more woodland had, perhaps not surprisingly, a richer diversity of bird species. Several species that favour forested areas (e.g. Spotted Pardalote, Crescent Honeyeater, Yellow-Throated Honeyeater, and Grey Shrike-Thrush) have declined in the Midlands over the past 20 years as more of their forest habitat has been lost. Increasing forest cover would therefore have significant benefits for native birds in the Midlands. Conversely, agricultural intensification has actually benefitted some birds, especially large-bodied grain-eaters (e.g. Galahs and Sulphur-crested Cockatoos) and raptors and other carnivorous birds (e.g. Swamp Harriers and Forest Ravens). Noisy Miners throw a spanner in the works! The presence or absence of Noisy Miners really affects species diversity – small-bodied species simply cannot co-exist with these very aggressive birds. Planting trees to increase available bird habitat will therefore only work if Noisy Miners are excluded. Miners prefer open woodland with little shrub cover, so plantings that maximise shrub cover and arrange trees in blocks rather than corridors may be most ‘miner-resilient’. As well as providing important advice for restoration managers, this study shows how valuable long-term data sets can be in helping to assess the impacts of environmental changes on bird populations. Keep up those surveys in your area! ______________________________________ Bain, G. C., MacDonald, M. A., Hamer, R., Gardiner, R., Johnson, C. N., & Jones, M. E. (2020). Changing bird communities of an agricultural landscape: declines in arboreal foragers, increases in large species. Royal Society Open Science, 7(3), 200076. https://royalsocietypublishing.org/doi/10.1098/rsos.200076 (The full paper is freely available to download at this site). .