Date: November 14, 2019
Source: Anglia Ruskin University
A new study has found that crows living in large social groups are healthier than crows that have fewer social interactions.
The research, led by Dr Claudia Wascher of Anglia Ruskin University (ARU), has been published this week in the journal Animal Behaviour.
Dr Wascher and her colleagues studied a population of captive carrion crows over a six-year period. They monitored the behaviour of the crows in different sized groups and measured friendship by ranking the birds using a sociality index.
At the same time, they studied the crows' droppings to measure for the presence of coccidian oocyst, a gastrointestinal parasite that can represent an important health threat for birds.
Increased exposure to parasites and disease transmission is considered as one of the major disadvantages of group living. This new study, however, shows the opposite effect.
The researchers found that crows with strong social bonds, living with more relatives, and in larger groups, excreted a significantly smaller proportion of droppings containing parasites than less sociable crows.
The study did not find a connection between health and the crow's dominance within the group, but found that male crows (33%) were slightly more likely to carry the parasite than females (28%).
Dr Wascher, Senior Lecturer in Biology at Anglia Ruskin University (ARU), said: "Crows are a highly social bird and we found that crows with the strongest social bonds excreted fewer samples containing coccidian oocyst, which is a common parasite in birds.