TY - JOUR
T1 - Behaviour of an alpine range-restricted species is described by interactions between microsite use and temperature
AU - Oswald, Krista N.
AU - Smit, Ben
AU - Lee, Alan T.K.
AU - Cunningham, Susan J.
N1 - Funding Information:
We thank the Lee family for allowing the research to occur on their property in the Western Cape, South Africa. We thank two anonymous referees for their valuable input and suggestions which have greatly improved our manuscript. We also thank the many field assistants, without which this work could not have occurred: Kate Beer, Ruby Merriman, Daniel Lambe-Hyner, Audrey Miller, Jenny Tartini, Kelly Jones, and Matthew Dunn. Lastly, we thank the volunteers who helped with initial project set-up and Rockjumper captures: Dean Portelli and Christina van Midden. This work was supported by a Nelson Mandela University Research Themes Grant (BS), a post-doctoral research grant from the South African National Biodiversity Institute (AL), and a grant from the DST-NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology (SJC).
Funding Information:
We thank the Lee family for allowing the research to occur on their property in the Western Cape, South Africa. We thank two anonymous referees for their valuable input and suggestions which have greatly improved our manuscript. We also thank the many field assistants, without which this work could not have occurred: Kate Beer, Ruby Merriman, Daniel Lambe-Hyner, Audrey Miller, Jenny Tartini, Kelly Jones, and Matthew Dunn. Lastly, we thank the volunteers who helped with initial project set-up and Rockjumper captures: Dean Portelli and Christina van Midden. This work was supported by a Nelson Mandela University Research Themes Grant (BS), a post-doctoral research grant from the South African National Biodiversity Institute (AL), and a grant from the DST-NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology (SJC).
Publisher Copyright:
© 2019 The Association for the Study of Animal Behaviour
PY - 2019/11/1
Y1 - 2019/11/1
N2 - 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 physiologically 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 temperature 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.
AB - 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 physiologically 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 temperature 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.
KW - alpine endemic
KW - behavioural buffering
KW - behavioural trade-offs
KW - climate relict
KW - microsite use
KW - range-restricted species
UR - http://www.scopus.com/inward/record.url?scp=85073019298&partnerID=8YFLogxK
U2 - 10.1016/j.anbehav.2019.09.006
DO - 10.1016/j.anbehav.2019.09.006
M3 - Article
AN - SCOPUS:85073019298
VL - 157
SP - 177
EP - 187
JO - Animal Behaviour
JF - Animal Behaviour
SN - 0003-3472
ER -