A subcutaneous transmitter with a trailing antenna is implanted under the skin most often at the base of the neck on the bird's back. A small incision is made and a long hollow needle is inserted under the skin where the antenna will be placed. The antenna is inserted into the needle which is used to pull the transmitter into place. The incision is closed with 3 or 4 stitches. Surgical techniques and surgical facilities are necessary.

There are several advantages of the subcutaneous transmitter. It does not encumber the wings or body. The body warms the transmitter which is helpful to battery life in cold regions. It has an aerodynamic profile, especially important for migrants such as doves.

Disadvantages are high handling and skill level requirements. Possibility of infection or rejection exists which could result in expulsion of the transmitter. The internal antenna limits field range.

Series	Weight (grams)	Description
A2800	5.1-9.7	Coin shape, horizontal antenna