Most GPS trackers can be divided into two categories:
1) Need it simply to locate a lost bird
2) Need real-time GPS tracking of a bird
Most of the current GPS trackers on the market like RF-V16 and TK-102B fall into Category 1. They operate as "call-and-respond" trackers, giving you GPS coordinates once you call the tracking unit, or perhaps have it text you those coordinates every minute.
Very few trackers fall into Category 2. One of them is the Flytrex Live 3G. It will give you continuous, real-time GPS location on a Google Maps satellite view as a red dot. Anywhere your bird goes, you see the red dot moving dynamically on a map. Obviously, this is rightfully considered overkill for somebody merely trying to locate a lost bird. However, for long distance flying beyond LOS, then it becomes a very important tool that can save your *** many times in knowing your orientation and getting your bird back home.