When I looked at this empty martin house, it made me think about all the life that filled it only a few weeks ago. I thought about those seemingly fragile young birds and their parents on their incredible journey to the south, and thought again about what a miracle this world is, and all the life that fills it. Safe journey, martins!
On a more technical note, here is an interesting link to an article about how to use Nexrad to track the migration event.
How to use Nexrad to follow migration
Take care, all, and thanks for reading!