Behaviour

Behaviour as heat stress mediator and its payoffs

Physiological thermoregulation in the heat is costly for endotherms, entailing large and rapidly increasing water expenditure, risks of blood chemistry changes associated with panting, and performance costs of adaptive hyperthermia. Changes in behaviour (e.g. reduction in activity) and microsite selection (choosing shaded, cool locations in the landscape) can reduce some of these costs by reducing the animal’s ‘heat load’. However, there is no such thing as a free lunch and these strategies (collectively called ‘behavioural thermoregulation’) carry their own baggage. This is because they require animals to alter their patterns of behaviour, and these alterations can carry significant fitness consequences.

In my research group, we study the effects of temperature on, and the knock-on consequences of this for various fitness proxies, including reproductive success and body mass changes. We look at species traits that may exacerbate or reduce these costs, for behaviour example foraging strategies that place individuals under excessive heat loads, or interactions between heat stress and already costly breeding systems. We are very interested in life-history strategies that may buffer individuals from the costs of thermoregulatory behavioural trade-offs, for example, group-living in arid zone birds, and how the structure of social groups is affected by heat stress.

We work on a range of Kalahari species including southern fiscals, southern yellow-billed hornbills, sociable weavers, white-browed sparrow-weavers and southern pied babblers. In the Fynbos biome, we address similar questions looking at cape rockjumpers and cape sugarbirds. 

Dr. Susan Cunningham, Principal Investigator

Sociable wavers, drinking, heat stress

Current Projects

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A trait-based approach to assessing the sensitivity and exposure of arid-zone birds to climate change

Dr Stephanie Payne (Post-Doc)

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Social status and thermoregulation

Michelle Thompson (Ph.D. student –– within her project:  validation of a behavioural index for assessing species’ relative vulnerabilities to rising temperatures)

Effect of temperature and resource availability on the reproductive ecology of an arid zone bird

Nicholas Pattinson (Ph.D. student)

Taking the heat: how do parent birds mitigate costs of breeding at high temperatures?

Benjamin Murphy (Ph.D. student)

Thermoregulation and microhabitat use by Dune Larks in the Namib Sand Sea

Jessica Roberts (M.Sc. student)

Hot City Birds: Influence of heat dissipation and junk food on foraging behaviour and body condition in an urban passerine

Miqkayla Stofberg (M.Sc. student)

Effects of high temperatures on nestling growth and physiology in the Southern Ground Hornbill

Carrie Hickman (M.Sc. student)

Completed Projects

2020

 

Amanda Bourne (Ph.D.)

 

Thesis: Can social behaviour, particularly load-sharing, buffer against fitness costs associated with heat stress?

Supervisors: Dr. Susan CunninghamProf. Amanda Ridley, Dr. Claire Spottiswoode

Collaborator: Prof. Andrew McKechnie

     Krista Oswald (Ph.D.)

Chapters within Thesis: Vulnerability of a Fynbos-endemic bird to climate warming: insights from past and present responses to high temperatures

Supervisors: Dr Ben SmitDr Alan LeeDr Susan Cunningham, Dr Shelley Edwards

Jack Harper (M.Sc.)

 

Assessing the climate change vulnerability of reptile and amphibian species in Table Mountain National Park

 

Supervisors: Prof. Wendy Foden, Dr Susan Cunningham, Dr Nicola van Wilgen

        Matt Orolowitz (M.Sc.)

Life on the Edge: Does body size dictate how birds deal with the heat in South Africa’s most extreme desert?

Supervisors: Dr Susan Cunningham

2018

Tanja van de Ven (Ph.D.)

 

Thesis: Implications of climate change on the reproductive success of the Southern Yellow-billed Hornbill, Tockus leucomelas

 

Supervisor: Prof. Phil Hockey, Dr Susan Cunningham, Prof. Andrew McKechnie, Prof. Peter Ryan

Dr Margaux Rat (Post-Doc)

 

Temperature and social structure

 

Supervisor: Dr Susan Cunningham, Prof. Andrew McKechnie, Prof. Cedric Sueur

2017

Ryan Olinger (M.Sc.)

 

Thesis: Hot Drongos - foraging, parental care and thermoregulatory trade-offs

 

Supervisors: Dr. Susan Cunningham, Dr. Tom Flower

 

 

Nicholas Pattison (M.Sc.)

 

Thesis: Seasonal physiological and behavioural responses of a small bird in an arid habitat

 

Supervisor: Dr. Ben Smit

2016

Penny Pistorius (M.Sc.)

 

Thesis: How air temperatures affects flight initiation distance in arid-zone birds

 

Supervisors: Dr. Susan Cunningham, Dr. Rowan Martin

2015

Salamatu Abdu (M.Sc.)


Thesis: Does the availability of shade limit use of water holes by desert birds?

 

Supervisors: Dr. Susan Cunningham, Prof. Peter Ryan, Prof. Andrew McKechnie

 

2014

Dr. Susan Cunningham (Post-Doc)

 

Temperature, parental investment and reproductive outcomes, Southern Fiscals

 

Phenias Sadondo (M.Sc.)


Thesis: The influence of temperature on parental investment in southern fiscals and consequences for nestling growth

 

Supervisors: Prof. Peter Ryan, Dr. Susan Cunningham, Dr. Rowan Martin

2011

Kate du Plessis (M.Sc.)


Thesis: Heat tolerance of Southern Pied Babblers in the Kalahari Desert: how will they respond to climate change? 

 

Supervisors:  Prof. Phil Hockey, Prof. Amanda Ridley, Dr. Rowan Martin, Dr. Susan Cunningham

2009

Justine Cordley (M.Sc.)

 

Thesis: Hot, hotter, gone? Predicting climate-induced species losses from hot African ecosystems 

 

Supervisor: Prof. Phil Hockey