OPINION
A familiar garden bird in an unfamiliar world
The Arctic has extraordinary light and temperature conditions. Winters are harsh with barely any sunlight, while summers have 24 hours of daylight and an abundance of resources, even if short-lived. These special conditions may pose interesting challenges to organisms: how do they know when to be active, breed, and migrate?
Typical Arctic animals are likely adapted to this light regime and to cope with the extreme temperatures, for example, by detecting very small changes in light intensity. But as temperatures rise with climate change and as cities spread to Arctic regions, other species increasingly move into areas where they were previously absent. How can these newcomers cope with such extreme environments?
My research focuses on one such newcomer: the great tit (Parus major), a small songbird familiar to many people from gardens and bird feeders across Europe. Great tits established themselves in northern Norway only around 80 years ago. Here in the north, this garden visitor is facing, as we speak, the challenge of adjusting to the Arctic environment.
Since 2023 we have been monitoring great tits on the island of Tromsøya in Norway. Today we have more than 250 nest boxes and 16 feeding stations spread out around the island, which we use to monitor over 60 great tit breeding pairs and their offspring every year.
As part of our study, my team gives birds a small leg ring containing a microchip. Each ring/microchip has a unique number and can be detected by readers placed in nesting boxes and feeding stations. That way, we know when birds are active or inactive based on their visits to boxes and feeders. It also lets us know who is still alive. We observe that some great tits are active throughout the whole day, while others have a very strong day/night rhythm. Whether one strategy is better than the other is a question we are still investigating.
In addition, we monitor our birds’ nests during spring and summer to learn when they lay eggs, how many eggs they lay, and how many chicks they successfully raise until independence. We expect that great tits that have already adjusted to the Arctic will be less affected by the harsh Arctic environment. That means we expect them to survive in greater numbers and also have more offspring. Our study will allow us to better understand how quickly newcomer populations can adapt when they move into new environments, such as the Arctic.
Our nest monitoring also supports further investigations about adaptation to climate change and urbanization. Common species like great tits are quite relevant for understanding adaptation because they allow us to observe evolutionary change as it happens, being a source of information to predict how biodiversity in general will respond to future environmental change.
As an Arctic Six Chair, I have the goal of connecting multiple great tit monitoring teams across Arctic Fennoscandia. Although great tits are widespread and well-studied songbirds across Europe, Arctic populations are still underrepresented in most studies about impacts of climate change and urbanization. Thus by using these datasets we can get a much better picture about population responses in one of the most rapidly changing environments in the world.
