From May 2007 birds were fitted with 15-gram,
radio transmitters, model RI-2B with a life span
of 24 months and made by Holohil Systems Ltd.
The RI-2B is designed as a necklace-mounted
transmitter. The transmitter rests on the bird’s
breast while the antenna loops around the neck
and emerges behind the head. The collar is
made of flexible elastic attached to the
transmitter at two point