As days get longer, hormones and restlessness increase. Many robin fights like this take place as winter flocks break up before spring nesting season, or when they arrive somewhere and want to establish a territory. The first robins to return and set up territory boundaries are often the ones that had that territory last summer. If their territories have good resources, like a birdbath, the "home" birds—both male and female—may have to spend a lot of time and energy chasing off other robins that migrate through. Explore more about territories in this week's report!
Photo: Andy Wilson