Playing with PIT tags

Posted on Feb 24, 2013

In addition to booking flights and making this website, I’ve spent the last week or so playing with plastic, glue, boiling water and sharp knives, all in the name of ‘provisioning rates’.

One of the aims of the project is to find out how the habitat makeup of a territory influences breeding success, via its influence on prey availability, foraging behaviour and chick diet. An important component of foraging behaviour is provisioning rate – the frequency with which parents deliver food to chicks – which, all other things being equal, should influence how much food the chicks get.

Rather than trawling through days of expensive video footage, or trying to directly observe provisioning rates, I’m going to try and measure it using RFID technology. We’ll fit a small (~0.1g, 12mm long) Passive Inductive Transponder (the same technology used to identify cats and dogs) to the leg of parent birds, and place an RFID  reader at each nest. When the PIT tag comes within range (~10cm) of the reader’s antenna (which will be directly beneath the nest hole entrance), the tag will emit a unique radio code, which will be logged by the reader. This will give us a record of how often each parent visits the nest.

RFID reader

RFID reader (photo from here)

The RFID readers are being built by an electronic technician in ENV (based in this design), and I’m trying to work out how to fit the PIT tags to the Rollers without interfering with the colour ring combinations used to identify birds visually. The PIT tags can’t be glued directly to the rings (I think they’d just fall off), so I’m going to mount the tag onto a bit of plastic which can then be glued (securely, given it’s larger area) to the colour rings (thanks to Dr. Malcolm Nicoll for the idea, and to Dr. Jenny Gill for her precious aluminium mould) – hopefully this will allow enough of the colour ring to be seen so that birds can still be identified by sight. 

The slideshow below will give you an idea of what I’ve been up to (it’ll also remind Phil and I what to do when we go into mass production).

If you’ve got any questions or comments, either use the comment form below or email me.

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