It started as a strong leisure interest with a focus on nature photography. But gradually an increasingly clear pattern emerged.
Young pigeon hawks made sudden lunges against branches, tossed dead mice into the air and rolled cones down steep slopes which they then chased. They were clearly engaged in play. Kind of like kittens.
- Then we started looking a little more seriously and systematically at all the material we had. And then we could see this development curve over time, which is so typical of play behavior in animals, says Johan Lind, researcher and first curator at the National Museum of Natural History in Stockholm.
Together with Måns Söderberg and Thomas Mras, he has followed nesting pigeon hawk pairs in the Stockholm area during the period 2017–2025. Now they present their observations in the journal Animal Behaviour.
The study shows that the play behavior begins when the pigeon hawks are about one and a half months old. Then it becomes more and more intense until about two months of age. After that, the behavior subsides and disappears when the cubs have to fend for themselves, at about three months of age.
- There is no school for wild animals, and no one else who takes responsibility after this period you have with your mother or father. So it is during that time that you have a window to engage in this type of behavior, says Johan Lind.
- Then you get food and protection from danger. Because play is both energy-demanding and risky. You can be killed by some other animal when you move around, he adds.
Previous studies have demonstrated spawning behavior in other species of raptors. But this is the first time that it has been established in pigeon hawks - and that the spawning behavior so clearly follows the typical developmental curve.
Per Jensen, who is a professor of animal behavior at Linköping University and has focused much of his research on play behavior in various animals, thinks it is an interesting study - even if the number of observations is relatively few.
- Play is a behavior that has gone under the radar for a very long time, but which probably has an enormous evolutionary significance. Nowadays, it has been established that most types of vertebrates play, including snakes, reptiles and fish. And last year there was a study showing that even banana flies seem to spawn if given the chance, he says.
He explains that you can roughly divide the game into three types. Partly object play, which the new study shows that the pigeon hawks engage in. Then there is social play, often with pretend aggression - and finally so-called locomotor play, where the animals move around wildly in different ways.
- It is a reasonable assumption that play helps the animals train abilities that are crucial for their survival, for example catching prey, hiding or managing social relationships. But so far, research has had a bit of difficulty showing that, says Per Jensen.
As an example, he cites studies that show that cats hunt just as successfully whether they were allowed to play or not when they were young.
- So we are actually still groping in the dark quite a lot when it comes to play behaviour. But if I were to put a penny on something, it would obviously be a form of training for adulthood.
And the driving force is a strong desire, he adds.
- We know that play is associated with very positive emotions in the animals. So while the dove hawk may look stern, I'm sure it would smile if it could.
