That's a good suggestion except we only own a camera. Maybe it is time to go for a camcorder and hide out on our porch.
I was thinking more along the lines of a webcam - very inexpensive piece of equipment. A good computer store could set you up with the right equipment .. hooks to your computer .. you can record what the camera sees.
Check that out before you spend lots of bucks for a CAM-Corder (which is different than a webcam).