Facts: This is how the study was done
The study was done on 188 tallow oxen in cities and out in the forest.
Two tail feathers were plucked from each bird and the level of the stress hormone corticosterone was measured in these.
The measured value shows how high the stress level was in the bird during the 20-30 days when the tail feathers were formed.
The tail feathers are formed in late summer and early autumn. During that period, flock formation takes place before winter, which means that the stress level is higher in the birds at that time.
Source: Anders Brodin, Department of Biology, Lund University
“One reason could be that it is easier to find food in the city,” says Anders Brodin, professor of theoretical ecology.
The Talgox is distinguished by its high cognitive ability and it easily adapts to different environments.
— Originally, they are adapted to the Central European deciduous forest belt, but they have adapted very well both to Norrland’s coniferous forests and to living in communities.
In cities, the talgoks are the most common species around the bird tables, and Anders Brodin describes them as masters at stealing food from people.
— They are very resourceful and can learn to knock on windows to get refills.
In the forest, the environment is simply a bit harsher, which creates stress. He believes that the study indicates that bird feeding is very important for species such as the tall gox to be able to live close to humans.
– It is probably also the case that the tallow beetles that once colonized these new environments were perhaps the most suitable. There has been some evolution so that they have had reduced stress responses. They have adapted to the new environment, says Anders Brodin.