The babies have learned to fly! Fat, feathered babies crowded into the nest so full of them that I thought they would fall out (how DO they sleep at night!) and finally they are flying.
The air over the back yard filled with birds they day they learned. It seemed the entire barn swallow community came to celebrate, to show them how it should be done, this flying business.
One bird stayed behind that day, huddled in the nest, watching. Noone bothered him. The next day or so, he was out there in the sky, indistinguishable from the others making circles in the air.
Each one learns at his own pace. Even in the bird world.