Pied Babblers and Fork-tailed Drongos
Tim Clutton-Brock originally established the Kuruman River Reserve to study group living in meerkats, but it has become the focus of several other long-running animal studies. Amanda Ridley’s Pied Babbler Research Project was initiated in 2003 and uses habituated, free-living groups of Southern Pied Babblers Turdoides bicolor to understand the causes and consequences of cooperative breeding behaviour. In 2006 Amanda expanded the study to include the local Fork-tailed Drongo Dicrurus adsimilis population, investigating interactions between drongos, babblers and other species. Tom Flower joined the Drongo Project in 2008 to continue research on species interactions, with a focus on the drongos’ use of false alarm calls to steal food from other animals. Recently, both Amanda and Tom have collaborated with Susie Cunningham to explore how increasing temperatures resulting from climate change will affect the reproduction and survival of babblers and drongos respectively in marginal desert environments.
The causes of conflict and cooperation in group-living societies
The Pied Babbler Research Project investigates the benefits of cooperation and the causes of conflict in this highly cooperative, group-living species. The study population of 12-19 groups has been monitored continuously for 15 years. Group size and number varies considerably according to weather conditions in the Kalahari, with the population suffering a considerable decline following breeding seasons with poor rainfall and high temperatures. The population also declines during very cold winters, when juveniles experience high mortality. Long-term life history data, along with short-term observations and experiments, have helped the team understand the causes and consequences of cooperative breeding behaviour. These findings help to reveal the benefits of cooperation not just in babblers, but from a broader evolutionary perspective.
How interactions between species shape animal behaviour
The Fork-tailed Drongo project explores how interactions with other species in an animal’s environment can shape the evolution of behaviour. The project focuses on a population of over 40 pairs of habituated and colour-banded drongos that are individually recognisable. Research has primarily focussed on the drongo’s deceptive use of false alarm calls, including mimicked alarms, to scare other species and steal their food. We are exploring how drongos learn both their repertoire of mimetic alarm calls and the deceptive tactics they use to steal food. In addition, together with Susie Cunningham, we are investigating the potential impact of climate change on bird persistence in hot desert environments. We consider whether increasing temperatures place thermoregulatory constraints on drongo foraging and offspring provisioning, thereby reducing survival and reproductive success. We are also investigating how drongos adjust their behaviour to reduce the impact of high temperatures on reproductive success, including through offspring shading, foraging tactics and even shifting to crepuscular or nocturnal activity.
Activities in 2017
- PhD student Amanda Bourne successfully completed her second field season on Pied Babbler behaviour and physiology and has submitted her first manuscript from this research. Amanda’s field season included several different experiments in addition to the collection of observational data. It was a very dry breeding season in the summer of 2017/8 and as a result, breeding success was very poor.
- Amanda Ridley’s student, Elizabeth Wiley, obtained her PhD from the University of Western Australia in November 2017. Her research on Pied Babblers revealed an impact of increasing heat and drought events on population dynamics. Elizabeth has published a paper from this research in Animal Behaviour, with several more in review.
- Martha Nelson-Flower used the long-term Pied Babbler database to comprehensively test new models for the occurrence of cooperative breeding with empirical data. Her paper will appear in a 2018 issue of Journal of Animal Ecology.
- Several papers on Pied Babblers were published, including on meaningful call combinations (Engesser et al. 2017. Animal Cognition) and the ecology of cooperation (Nelson-Flower et al, 2018 Journal of Animal Ecology).
- Amanda Ridley and Martha Nelson-Flower were invited to contribute to a new book on cooperation and conflict published by Cambridge University Press.
- Pied Babbler and Fork-tailed Drongo research was presented at several national and international conferences.
- CB MSc student Ryan Olinger graduated in June 2017. His findings will shortly be submitted for publication in Global Change Biology and will provide the first behavioural evidence that increasing temperatures associated with anthropogenic climate change decrease bird foraging because of the thermoregulatory constraints, and not just a decline in food availability.
- Tom Flower was an invited speaker at the “Fear: Brain, Behaviour, Society” conference hosted by the Aarhus Institute of Advanced Studies Conference, Denmark. Tom’s talk was titled ‘Risky information: Animals use deceptive communication to manipulate FEAR responses’.
- Tom Flower’s participation at this conference has resulted in him leading a group drafting a review manuscript on the evolution of fearmongering in animal communication, which takes an interdisciplinary approach from microbiology to human politics.
For more details on the collaborative work between the Pied Babbler and Fork-tailed Drongo Projects and the Hot Birds Project, see the Hot Birds Project section of this report.
DST-NRF CoE grant; Australian Research Council.
Assoc. Prof. Amanda Ridley (FIAO, UCT and UWA)
Dr Thomas Flower (FIAO, UCT and Simon Fraser University)
Dr Matt Bell (U. Edinburgh)
Dr Martha Nelson-Flower (U. British Colombia)
Dr Susie Cunningham (FIAO, UCT)
Prof. Claire Spottiswoode (FIAO, UCT and U. Cambridge)
Prof. Andrew McKechnie (U. Pretoria)
Dr Simon Townsend (U. Zurich)
Students: Elizabeth Wiley (PhD, UWA); Amanda Bourne (PhD, UCT); Ryan Olinger (CB MSc, UCT).
Research assistants: Rita Leal, Sello Matjee.