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Hot droughts compromise interannual survival across all group sizes in a cooperatively breeding bird

posted on 30.07.2020, 14:30 by Amanda Bourne, Susan Cunningham, Claire Spottiswoode, Amanda Ridley
Climate change is affecting animal populations around the world and one relatively unexplored aspect of species vulnerability is whether and to what extent responses to environmental stressors might be mitigated by variation in group size in social species. We used a 15-year dataset for a cooperatively-breeding bird, the southern pied babbler Turdoides bicolor, to determine the impact of temperature, rainfall, and group size on body mass change and interannual survival in both juveniles and adults. Hot and dry conditions were associated with reduced juvenile growth, mass loss in adults, and compromised survival between years in both juveniles (86% reduction in interannual survival) and adults (60% reduction in interannual survival). Individuals across all group sizes experienced similar effects of climatic conditions. Larger group sizes may not buffer individual group members against the impacts of hot and dry conditions, which are expected to increase in frequency and severity in future.


This work was funded by the DST-NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, the University of Cape Town, the Oppenheimer Memorial Trust (Grant No. 20747/01 to ARB), the British Ornithologists’ Union, the Australian Research Council (Grant No. FT110100188 to ARR), a BBSRC David Phillips Fellowship (BB/J014109/1 to CNS), and the National Research Foundation of South Africa (Grant No. 110506 to SJC).



FitzPatrick Institute of African Ornithology