Birds on farms: a review of factors influencing bird occurrence in the temperate woodlands of south-eastern Australia

Abstract

Australia’s temperate woodlands are among the most heavily modified biomes globally. I summarise some of the work on birds in south-eastern Australia that identifies drivers of bird biodiversity loss and the effectiveness of management interventions. I particularly focus on studies by the Sustainable Farms project at The Australian National University which show that: (1) Bird occurrence is associated with the amount of woody vegetation cover at site, farm and landscape scales. (2) Planting to increase woodland cover has greater relative positive effects on birds than grazing control. However, grazing of plantings has inherently negative impacts. (3) There are different broad structural types of woodland (old growth, regrowth and replantings) and each supports different bird assemblages. (4) The highest bird biodiversity occurs on farms which support all three woodland structural types, as well as other natural assets like paddock trees and fallen timber. (5) Long-term data show that while some woodland species are increasing, twice as many species are declining. Despite the body of information on woodland birds, substantial knowledge gaps remain. These include understanding of: (1) the role of fire in woodland bird dynamics and habitat suitability, and (2) demographic processes like bird breeding success and how it affects long-term site occupancy. Bird biodiversity in Australian agricultural landscapes formerly dominated by temperate woodlands will be best supported by: (1) ceasing land clearing, (2) greater woodland regeneration and woodland planting, (3) limiting livestock grazing, and (4) limiting the impacts of the Noisy Miner (Manorina melanocephala).