Observing other sick birds triggers an immune response in healthy canaries. This is the conclusion reached by a team of researchers from the University of Oklahoma and the University of Arkansas (United States). In addition, the results of the research have been published in the journal Biology Letters, where the scientists describe the experiments they carried out with the birds.
Previous research has shown that many animals (including humans) avoid others of the same species when they show signs of illness. But for some animals, being separated from their group could be riskier than getting sick.
Birds depend on their group for protection. Therefore, they have developed another strategy to avoid getting sick. Researchers have been able to observe that, in at least one species of bird (canaries), the simple fact of seeing others of the same species fall ill is more than enough to initiate an immune response.
Study development
The researchers placed two groups of canaries in separate cages, facing each other. And then they (slightly) infected one of the groups with a bacteria.
In addition, they were careful and placed uninfected birds far enough away from sick birds to prevent them from catching it as well.
As the team of scientists points out, the symptoms of the infection made the birds appear very sick. In fact, the birds developed conjunctivitis, which is why they were practically lethargic.
The researchers monitored what was happening over the course of a month, taking blood samples and taking notes on the appearance of the sick birds.
Research findings
The researchers found that as the infected birds began to look sick, the immune systems of the healthy birds began to respond.
Similarly, the team was able to determine through a CH 50 test that the immune activity of all healthy birds had increased, especially those that could see the group of sick birds more closely.
The scientists also performed a white blood cell count. However, the cytokine levels of the birds did not change.
Ashley C. Love et al. Perception of Infection: Disease-Related Social Cues Influence Songbird Immunity, Biology Letters (2021). DOI: 10.1098 / rsbl.2021.0125
