How do falcons have babies?

Today, Feb.13, 2011 my husband called me outside to watch a falcon that had apparently picked another bird out of the air. Both birds crashed onto a rooftop and then fell to the ground. We watched from a distance.

My husband thought that the falcon killed the large bird on the roof and was now trying to lift its prey from the ground. "Is it a duck?" I asked. "No," he said, "I think it might be a crow or something."

We continued to watch the struggle on the ground, and at one point I asked, "Well is that another falcon?" It looked to me like the underneath bird was either a large bird of prey or another falcon.

The struggle continued for several minutes on the ground, and then both birds, falcons as it turned out, stood up and flew away.

We surmised from this that the falcons were mating and that they mate on the ground. The interaction seemed incredibly violent. We could hear them crash into the roof from a distance of 80 to 100 yards. On the ground, from a distance it looked like a predator-prey situation.