Hi,
I would like some suggestions of good drop off mechanism for collar (e.g. designed for larger Cervidae)? Carrying a load of about 500 gram.
Regards,
Ronny
HI,
If the duration of study is around one year, I would use any after-market drop-off devices from LOTEK or Sirtrack etc. However, I do not trust the device to work if it is longer, say two years, from my experience. Regardless of duration, I will add some strip of cotton to the belt as weak link.
500 g sounds pretty light for Cervids living in Norway. If you are planning to collar newborn animals, some elastic material could be ideal due to its elasticity and bio-degradablity.
I have used the Vectronics drop-off system on 500g GPS collars on Arabian tahr. I used the preprogramed version where you specify the number of days the collar remains on before deploying, based on battery life expectation, and then it is not possible to reprogram the drop-offs remotely. The counter then starts after a special magnet is removed. The system is a simple 2 pin release mechanism attached to the battery pack. We had 100 percent success on 18 collars, their collars also worked well for us. The system added 70 grams of weight to the collar. They also do a remote drop-off system where you have to get within 2km of the animal to be able to release using a UHF transmitter, this would have been difficult for us. Good Luck
If a passive drop-off system would meet your needs, you might look at the attached publication.
I agree with Masao, however difference in reliability depends highly on the environmental conditions. Working in dry and wet tropical environments, I experienced more issues (failures) with mechanical release mechanisms in humid environment.
Especially, if humidity and mud comes together, most mechanical drop-off systems have high probability of failure.
However, dry (or cold) climatic conditions may result in much slower decomposition rates than expected, involving the need of thinner material for the breakaway line and thereby higher variability in release/degradation time.
I used Televilt collars on the Corsican red deer in 2009. I chose to activate collar release by the remote controlled drop-off mechanism. In some case the collar recovery was easy because immediately the device fell to the ground, in other case I have waited one week or more for collar recovery after activation the drop-off mechanism. This problem probably was due to presence of the mud in the collar or rust in the compression spring of the mechanis. I attach one photo.
Hi Ronnie,
I have used drop off collars from Vectronics but on tigers. One out of 12 drop offs didn't drop. I used the UHF transmitter mechanism that Steven mentioned for all 12 collars. On the one which would not work I also used the programmed drop off mechanism (as you can change the drop off time with the UHF transmitter as well). My feeling is that if for whatever reason the drop off mechanism gets damaged (humidity for example, as tigers swim), it does not really matter the release method; it will not drop. However, as I said, it only happened to 1 out of 12 collars. I hope it helps. Good luck!
Interesting discussion, any news about those drop off mechanism? Some tried self built drop off mechanism?
We use a self built drop off mechanism.
It is made by cotton textile from old jeans.
They are decomposed in one/two years and fall from the animal neck.
Thank for sharing the experience, did you try other material or do you have an idea of other material duration?
I case someone is interest and handmade one here: https://www.instructables.com/Remote-Control-Drop-Mechanism/
Hi Antione,
I believe the drop mechanism https://www.instructables.com/Remote-Control-Drop-Mechanism/ is developed for dropping items from UAVs and the like. I belive the power consumption of the RC receiver and servo would make it unsuitable for use as a collar or sensor device drop mechanism.
- Badges
- Science method
- Similar topics
- Biological Science
- Ecology