Contrary to long-held belief, the size of a bird’s posse does not play a key role in helping them survive hotter, drier climates according to a new study by The University of Western Australia.
Long, hot weather events are a threat to wildlife populations globally and certain animal groups have become more cooperative, living together and helping one another, for protection from these highly variable climates.
To test this theory, a team from UWA’s School of Biological Sciences and the University of Cape Town assessed 15 years of data on pied babblers to investigate how the long-term impacts of climate change had influenced their survival and development in relation to group size.
The study, published in Ecology Letters, found that bigger group sizes, did not protect individual birds from these climatic extremes, with their populations severely compromised over time.
“This finding could be widely applicable to many wildlife species globally, especially in Australia with its rapid warming and drying landscape.”Associate Professor Amanda Ridley
Pied babblers live in the Kalahari region of southern Africa, an area that has extremely hot summers and is susceptible to drought conditions, similar to the Australian outback.
The researchers monitored the birds’ breeding outcomes, survival and body mass over time and found the combination of hot and dry conditions had detrimental impacts on both the adults and juveniles.
The adults suffered a 60 per cent decline in survival and a significant loss in body mass while the juveniles experienced an 86 per cent reduction in survival during hot droughts.
Additionally, there was a significant decline in juvenile growth rates, resulting in a lower body mass at maturity.
Lead author PhD student Amanda Bourne said while cooperation may be beneficial in variable climates for some species, the results showed considerable population decline during years of hot drought.
“Importantly, group size was not a good predictor of survival or body mass during these climatic events,” Ms Bourne said.
Co-author Associate Professor Amanda Ridley said even though the species was endemic to the warm-hot Kalahari region, it could still be strongly impacted by increasing temperatures.
“This finding could be widely applicable to many wildlife species globally, especially in Australia with its rapid warming and drying landscape,” Associate Professor Ridley said.
“That these weather events are increasing in frequency suggests that climate change may severely threaten future population viability of many species.”