Poor Calvin. Here he was sitting in my lap while I worked on the computer in my craft room, just minding his own business, purring contentedly. Suddenly, some chirping, a tap on the window, and he's up in the window box crouching in predator mode.
A little chickadee was teasing him mercilessly. The little thing would perch on the windowsill, tap the window several times, then fly into the bush right outside the window. After a while, it bored of its game and flew away.
Calvin was left sitting in the window for a very long time. He's always optimistic that his prey will come back to him. This actually reminded me very much of when a squirrel teased him horribly.
On days like this, Calvin wishes more than ever that I would let him be an outdoor cat.