The Crow should think again

I put up a nesting box in my garden and waited to see if anyone needed a home. The very same day a pair of Blue Tits moved in. I decided to set up a motion-activated camera to capture their activities. In one clip, a crow turns up and tries to turf them out. They fight back vigorously despite their smaller size, and drive the crow off. Then I realised something about the Blue Tit, and the resulting allegory was irresistible. The poem is short, but I hope it says it all. You can read it here.