An interesting article. One of the main considerations for any tracking research is whether the tracking device ma affect the birds, so I'm sure this finding will lead to a change in the approach taken on kites. Note that the article only applies to these devices on this species - it may not apply to other species.
Most tracking devices are designed that they would fall off after a limited time, when the data have been collected, and they would not have a long-term effect on the birds involved. A recent example in HK is the duck satellite tracking, where only one tag stayed on the bird for a full year. Author: Sze Time: 24/09/2011 11:44
John, thanks you so much for your information. I am interested that how can the researchers to control the duration of the tracking devices sticking on the birds? Would you mind to share more information to us? Thanks a lot! Author: ajohn Time: 24/09/2011 18:11
There are various methods and it depends upon the type of bird, the type of tag and the objectives of the study. The selection of an appropriate tag is the most important first step in any study.
Some tags are attached to feathers (often on the tail feather or glued to the bases of feathers on the back). These will be lost when the bird moults those feathers, so should last for a few months at most.
Harness transmitters can be fitted with a 'weak link' which is biodegradable in some way. Over time and with exposure to the weather, the 'weak link' will break and the harness will fall off the bird.
Recent advances with data loggers involve tags which will stay on the bird. These only collect/store data and do not transmit like radio-tracking devices, so they should not affect the health of the bird. Such studies then require that the bird is retrapped and the tag removed to collect the data. Author: Sze Time: 25/09/2011 00:50
Very useful information!
John, thank you so much for your sharing again!
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