Abstract
Large portions of the world’s forest are currently impacted by declines in tree health, however the impacts of these declines on woodland birds is largely unknown. Since 2002, small patches of Eucalyptus wandoo woodlands in the wheatbelt of southwest Western Australia have demonstrated decline in condition. Retraction or loss of canopy foliage can result in reduction in foraging resources such as nectar and pollen; insects, lerps and manna, and can also reduce habitat quality and nest sites for woodland birds. To investigate the influence of tree decline on bird foraging, we conducted observations of five bird species (rufous treecreeper, wattle bird spp., yellow plumed honeyeater, weebill and striated pardalote) on trees in various states of health in Dryandra State Forest and Wandoo Conservation Park. We observed birds by following flocks or using the sit-and-wait approach. Responses measured include the health of trees utilised, time spent within trees and the activity of each bird. Birds used both healthy and declining trees for their foraging activities; however, each individual species of bird demonstrated dissimilar preferences for healthy and declining trees. Striated pardalotes were never seen foraging on focal trees categorised as declining and weebills similarly displayed a preference for trees with low amounts of dieback in the canopy. In contrast, wattlebird spp. did not show a preference for the health of trees. Although the decline of E. wandoo may have temporarily affected resource availability for canopy foraging species (e.g. striated pardalotes), the patchy nature of the decline is likely to have had minimal influence on the food resources for the overall woodland birdlife.