Behaviour of an alpine range-restricted species is described by interactions between microsite use and temperature Krista N. Oswald a, b , Ben Smit a, b, * , Alan T. K. Lee c, d , Susan J. Cunningham d a Department of Zoology & Entomology, Rhodes University, Grahamstown, South Africa b Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa c School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa d FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa article info Article history: Received 3 May 2019 Initial acceptance 12 June 2019 Final acceptance 7 August 2019 MS number 19-00305R Keywords: alpine endemic behavioural buffering behavioural trade-offs climate relict microsite use range-restricted species Climate change predictions include increased mean temperatures and increased frequency of heatwaves. Short-term responses to high air temperatures can allow animals to conserve water while maintaining a safe body temperature. For birds, cooling is often through evaporative water loss, which can be physi- ologically costly. Microsite use is an effective means of conserving water via reducing environmental heat load, so long as there are no negative trade-offs with other necessary functions, such as foraging. We examined behavioural responses to temperature in Cape rockjumpers, Chaetops frenatus (hereafter: ‘rockjumper’), an alpine specialist bird. We hypothesized that rockjumper behaviours would be tem- perature and microsite dependent. We collected data on rockjumper microsite use (sun, rock shade), behaviour (activity, foraging, preening, panting) and temperature (air, environmental). Rockjumpers made increased use of rock shade as air temperature increased. However, birds in rock shade foraged less. Depending on where their main food source is located, this suggests that when foraging demands are high, birds may need to remain in the sun despite risks of high thermal load, or else may suffer costs of lost foraging opportunities when using shade. The relationship between air temperature and heat dissipation behaviour (panting) was also mediated by microsite: birds showed significant increases in panting with increasing air temperature only when in the sun. The lack of increase in panting for birds in rock shade suggests that shade seeking may buffer physiological thermoregulatory costs (i.e. water expenditure). Individuals may therefore be able to mitigate some potential negative effects of high temperatures by making use of cooler microsites, although this could come at a cost to foraging. © 2019 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. Under climate change, weather patterns are increasingly char- acterized by warmer overall temperatures and more intense heat- waves (Easterling et al., 2000). One way in which animals may respond quickly to environmental challenges is by using short-term behavioural responses (Wingfield, 2003). In general, behavioural responses to temperature have been considered typical of ecto- therms (e.g. Adolph, 1990; Gifford, Clay, & Powell, 2012; Gilman, Toolson, & Wolf, 2008; Huey, 1991; Huey, Peterson, Arnold, & Porter, 1989; Sears et al., 2016), while endotherms are often assumed to rely primarily on physiological adjustments to regulate their body temperatures (Boyles, Seebacher, Smit, & McKechnie, 2011; Chamane & Downs, 2009; Smit, Harding, Hockey, & McKechnie, 2013). However, when examining potential avenues for mitigating the negative effects of increasing temperatures, Huey et al. (2012) suggested that any terrestrial species in thermally heterogeneous environments could use ‘behavioural buffering’ (e.g. spending more time in cooler microsites) to help maintain body temperature. Indeed, behavioural buffering is a commonly used behavioural mechanism for coping with high temperatures, along with reducing daily energy expenditure, across both ectothermic and endothermic taxa (Buckley, Ehrenberger, & Angilletta, 2015; Gifford et al., 2012; Mugaas & King, 1981; Sinervo et al., 2010; Visinoni, Pernollet, Desmet, Korner-Nievergelt, & Jenni, 2015). Interest in behavioural buffering has led to a growing number of studies focusing on how endotherms use microsites to cope with high temperatures, including both birds (e.g. Cunningham, Martin, & Hockey, 2015; Hill, 2006; Martin, Cunningham, & Hockey, 2015; Pattinson & Smit, 2017; Shi, Paull, Broome, & Bates, 2015; Wolf, Wooden, & Walsberg, 1996), and mammals (e.g. Hewson, 1990; Moyer-Horner, Mathewson, Jones, Kearney, & Porter, 2015; and * Correspondence: B. Smit, Department of Zoology & Entomology, Life Sciences Building, Barratt Complex, African Street, Grahamstown, 6139, South Africa. E-mail address: b.smit@ru.ac.za (B. Smit). Contents lists available at ScienceDirect Animal Behaviour journal homepage: www.elsevier.com/locate/anbehav https://doi.org/10.1016/j.anbehav.2019.09.006 0003-3472/© 2019 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. Animal Behaviour 157 (2019) 177e187