Long-term attachment of GPS loggers with tape on Great Cormorant Phalacrocorax carbo sinensis proved unsuitable from tests on a captive bird

In preparation for a field study on wild birds, we conducted an experiment on captive Great Cormorants Phalacrocorax carbo sinensis to evaluate methods of attaching GPS loggers. Loggers (65 g) were attached to two injured cormorants in a bird rehabilitation centre. One logger was attached to the first bird with TESA tape and another logger to the second bird with a teflon harness. The taped logger was attached on the lower back, and subsequently on the upper back and the tail. This logger was removed within 10 (lower back), 4 (upper back) and 15 (tail) days by the cormorant biting off and pulling out the feathers to which it was attached. The logger deployed with the teflon harness on the second bird stayed on for 21 days, after which we removed it undamaged.