A study provides evidence of change in reaction to alert calls in great tits with an increase in ambient temperature

The world we live in is an excellent indicator of our behavior. In most bird species, vocalizations and various calls are the main form of communication between and beyond species. Communication allows us to utilize different escape tactics, mating rituals, and overall conversation. But what happens to this communication when our environment changes?                                                                     

With increasing temperatures and a general change in climate, researchers have found in the great tit (Parus major) that as temperatures rise, responses to mobbing calls vary when compared to patterns of calls in moderate temperature conditions. 

Mobbing calls are a type of alarm call used to harass predators, ward them off, and also allow others to escape. This mobbing call will also recruit other great tits to join the mob and continue to harass the predator. These calls are used during periods of potential attack as a life-saving signal. Any interference with the ability to signal in this way could lead to population declines and overall ineptness in an ecological context. Researchers suspect that increases in environmental temperatures can lead to changes in their ability to either make or respond to these calls. 

A study published in Behavioral Ecology and Sociobiology on July 3, 2023, finds that with increases in external temperatures, great tits change their response tactic to mobbing calls from “active defense to less active response” [1]. Meaning that they are less likely to respond aggressively to various mobbing calls from other great tits. This study also showed that the temperature during their study affected the number of mobbing calls the focal bird emitted.

The scientists used a loudspeaker to play predetermined mobbing calls at various temperatures both above or around the external average. They then measured how close the great tits approached the speaker, representing their normal response to mobbing calls. The scientists also noted whether or not there were any vocalizations from the focal bird. If there were, the calls were measured related to the immediate and average temperature of the environment. Sure enough, as the average temperature increased, the great tits responding to this mobbing call stayed farther away from the loudspeaker, breaking the normal pattern of coming closer to join the mobbing calls emitted by the focal bird. In addition, the scientists also uncovered that as immediate temperatures increase, the number of bird vocalizations also increases. 

This study determined that with mass temperature fluctuations, there are changes in mobbing calls. This demonstrates an example of stabilizing selection: The more moderate and average temperatures will display a normal call mobbing call response. However, we still do not know exactly why this behavior changes. There has been some research to show that as temperature increases, overall exertion of efforts is more difficult to task. The results could indicate that the great tits are just saving energy in hotter temperatures due to this high exertion. This adaptation is beneficial for the great tits at the moment. However, we need to question how this change in temperature will affect the population in years to come. Will there be more adaptation, or will great tits forever play a game of “broken telephone” ?

 

Cited: 

[1] Cordonnier, M., Ridley, A.R., Lengagne, T. et al. The impact of high temperatures on bird responses to alarm calls. Behav Ecol Sociobiol 77, 82 (2023). https://doi.org/10.1007/s00265-023-03354-2

[2] Hand drawn family, Social Messaging & Productivity Handrawn Doodle-pack by iBrandify, Altered under Public Domain https://www.iconfinder.com/search/icons?family=hand-drawn-43

[3] Web cartoon pack, Bird by Shlyapnikova, Altered under Public Domain

https://www.iconfinder.com/iconsets/Icons_Pack___Web_Cartoon___by_shlyapnikova

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