biologists place GPS transmitter backpack on a white-faced ibis

Biologists place an external solar-powered GPS backpack transmitter on a white-faced ibis. The bird was weighed and measured to ensure the transmitter was no more than 3-5% of the bird's body mass. These backpack transmitters collect data every 15-60 minutes, including the date, time, temperature, battery life, latitude, and longitude. That data is then downloaded once per day.