Why do birds do that?

This morning, on my way to work, I saw a bird "swoop" down in an arc shape in front of my SUV and land like a pendulum in the tree on the other side of the road. The funny thing is, birds seems to always do that, just seconds before crossing my path risking their life. Have they no sense of self-preservation or are they just making a bet with their buddies saying, "Hey, I bet you my seeds that I can fly in front of that vehicle and not get killed."? What's with them?