Friday, September 19, 2014

Radio transmitters and young tuatara

Attaching radio transmitters is a good way to study tuatara, lizards, and snakes. Because, you can't just watch a cryptic animal. But tracking it via radio transmitters means that the animal will just go about its life and you can tune in without effecting its behavior. But, for adult Tuatara, it's known that this works. But for young tuatara, not so much. So, there are studies on how radio transmitters effect young tuatara.

There were both tagged tuatara and untagged tuatara released into a natural area. It was evaluated whether or not there is an effect on growth, behavior, and body weight on tagged and untagged tuatara. Another method was using dummy transmitters such as clay molds, beads, or broken transmitters. Both dummy and functional transmitters had cylinders so the tuatara could be harnessed.

Methods for tracking
Do you ever think about reptiles with backpacks? If you do, then you'll understand this method. Straps were made out of elastic, and there were stitches so that the transmitter would sit by the neck of the tuatara in question. The next method:duct tape. Yes, duct tape can be used for anything, even tracking reptiles! The tape was wrapped around the tail of the tuatara, so that the transmitter would sit at the tail. This method was known as "surgical tape". But the next method-a variation of "surgical tape" with you guessed it, duct tape. Duct tape lasts longer than other tapes, but it might scar the reptiles. (physically, not emotionally.) Another method is a harness that holds the transmitter on the animal's back. It was secured with elastic, and the transmitter was held in place by a knot.

Methods for tracking cont.
For the backpack harness, it remained attached, but it swelled up the tuatara's shoulder. But contrasting, in less than 30 days, the tuatara shed the surgical tape method. But duct tape stayed, and some good news:from the tape, there is no injury. Now, for the translocation (moving the tuatara somewhere else), the backpack harness was used as it would last for the 5 months of the study, including when the reptiles shed their skin. However, modifications to the elastic and cylinders made it less likely the reptiles would get injured by the backpack harness.

Main study methods
The tuatara were released in spring, when they will have increased temperatures and activity. 14 wild-caught tuatara were released, as were 41 captive-raised tuatara. 2 more were then released.

 Results with juvenile tuatara
Four juveniles had implants in their abdomens, and they came from Stephens Island.  The implants stayed in for less than a month. Data was collected surrounding movement and habitat use, but there was no data surrounding negative effects. Another set of 2 juveniles were translocated to the Titi Islands. They had the backpack harness, that stayed for around 2 months. There was data collected about their movements and how spread-out they were. But there is good news. No negative effects were observed!

Study results
Three juveniles escaped from their harnesses, but they were found and their harnesses replaced. However, one tagged individual was found dead about 3 months from release, but it was probably due to a human crushing it, either purposefully, or accidentally by not watching where they stepped. But one main thing that is important is that tagged juveniles did fine. There were not negative effects on growth, weight, or how spread out they were. But how spread out they are is essential for re-introducing them to certain areas. The backpack harness did not effect the behavior of the tuatara. Both tagged and untagged animals had the same behavior. Radio transmitters are a good method for research of cryptic species, and they do not effect the behavior of juveniles.

Jarvie, Scott, Ramirez, Edward Dolia, Jignasu, Adolph, Stephen, Seddon, Philip, Cree, Alison. "Attaching Radio Transmitters Does Not Affect Mass, Growth or Dispersal of Translocated Juvenile Tuatara (Sphenodon punctatus)" Herpetological Review, 2014, 45(3).

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