For larger waterfowl, such as swans, where the researcher needs satellite connectivity to receive data, the Iridium Waterfowl Collar is a great option.

The collar starts at 150g, but can be built to your specification in terms of inner diameter based on species.

Iridium data is $12-40/month per unit depending on the amount of data being sent. An Iridium contract must be signed with CTT prior to delivery. Additionally, an Iridium activation fee and data usage for testing will be charged in the first month.