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Chronic stress in superb fairy-wrens occupying remnant woodlands: are noisy miners to blame?

Citation

Bain, G and Johnson, CN and Jones, M, Chronic stress in superb fairy-wrens occupying remnant woodlands: are noisy miners to blame?, Austral Ecology ISSN 1442-9993 (In Press) [Refereed Article]

Abstract

Interactions between competing species may be intensified when they are restricted to small patches of remnant habitat, potentially increasing physiological stress in individuals. The effects of interspecific competition on stress in wildlife remain largely unexplored. In Australia, remnant woodlands are often dominated by aggressive honeyeaters, especially the noisy miner (Manorina melanocephala). Harassment of smaller birds by miners may result in their exclusion from suitable woodland habitat. We tested whether the presence of noisy miners is also associated with elevated stress in a model species of small passerine bird, the superb fairy-wren (Malurus cyaneus). We sampled wrens from six sites, three remnant woodlands with noisy miners and three larger fragments of reserved habitat without noisy miners. Differential white blood cell counts were used to infer levels of chronic stress. We also assessed variation in body condition and the prevalence of blood parasites (Haemoproteus spp.) to test for associations between stress and parasitemia. The mean heterophil to lymphocyte (H:L) ratio was 1.8 ⨉ higher among superb fairy-wrens living in miner-dominated woodlands, suggesting higher levels of chronic stress. Individuals with higher stress appeared to be in poorer condition, as indicated by fat scores and residual body mass. Prevalence of blood parasites was generally high and was highest in reserved habitat (59%) where miners were absent. Birds with blood parasites living in these habitats had higher H:L ratios but the intensity of infection and H:L ratio was inversely related. Our results suggest that birds persisting in the presence of noisy miners might experience chronic stress, but further study is necessary to separate the relative importance of noisy miner aggression from other potential stressors in small patches of degraded woodland. Stress induced by interspecific aggression should be considered in future studies of wildlife living in remnant vegetation.

Item Details

Item Type:Refereed Article
Keywords:blood parasites, chronic stress, habitat fragmentation, interference competition, noisy miner, invasive species, conservation, woodland birds
Research Division:Environmental Sciences
Research Group:Environmental Science and Management
Research Field:Conservation and Biodiversity
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Farmland, Arable Cropland and Permanent Cropland Flora, Fauna and Biodiversity
UTAS Author:Bain, G (Mr Glen Bain)
UTAS Author:Johnson, CN (Professor Christopher Johnson)
UTAS Author:Jones, M (Associate Professor Menna Jones)
ID Code:132372
Year Published:In Press
Funding Support:Australian Research Council (LP130100949)
Deposited By:Zoology
Deposited On:2019-05-06
Last Modified:2019-05-21
Downloads:0

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