Shep,
When you check back, listen for a thin insect like buzzing. The parents will be around, and they will let you know they aren't happy.
Here is a link to its vocalization:
http://www.mbr-pwrc.usgs.gov/id/framlst/Song/h7510so.mp3 For as tiny as they are, they have a big attitude. Fun birds to watch. During spring turkey season this year, I had one land about 6 inches above my head on a branch and cuss at me for a quarter hour! These are neotropical migrants, they will leave in mid September and head back to central america during our winter.
Owl,
Can't take credit for the pics, just did a quick internet search to find a good pic. Been birding for 15 years now, and it is a great tie in with archery. When the turks or whitetails aren't cooperating, I still get a lot out of the experience by birding during the hunt.