Crow mobbing Herring Gull

Crow mobbing herring gullFrom my office, I hear a crow calling. I look out of the window and I just glimpse a Carrion Crow chasing a Herring Gull. Crows have a nest nearby, and are prone to defend the area around the nest from potential chick predators. The action happened too fast for me to grab my camera, so I drew this sketch to remember the event.