BRANTA — Marta Cálix
Environmental Correlates of Ring Ouzel Turdus torquatus abundance in the UK in 2012
Institution: University of Reading, UK
Supervisors: Innes Sim
Details: MSc 2014 (completed)
Subject Keywords: Ring Ouzel, environmental correlates, territory counts
Species Keywords: Ring Ouzel Turdus torquatus,
Ring ouzels Turdus torquatus are a UK Biodiversity Action Plan priority species due to a reduction of over 50% in population numbers over the past 25 years. Using the 2012 National Survey data, the environmental correlates of ring ouzel abundance were modelled with Zero-Inflated Negative Binomial regression following an Information Theoretic approach. Topographical variability, percentage heather cover, and the interaction between mean tetrad altitude and the percentage cover of rough grassland showed a significant positive correlation with maximum number of ring ouzel territories per tetrad, whereas the percentage cover of coniferous woodland showed a significant negative correlation. False zeros were more likely to occur in tetrads with lower mean altitude, and in tetrads with lower heather, heather grassland, rough grassland and inland rock percentage cover. The results are similar to several regional studies of ring ouzel populations, providing support for the hypothesis that regional level predictors of tetrad occupancy and ring ouzel abundance are also useful at the UK level.