Wildlife Research

Dale Matson

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I was backpacking near Reflection Lake and took a photograph of a deer with two tracking collars. Why would there be a need for two collars? 

From: "Gammons, Daniel" <daniel_gammons@nps.gov>

Date: Friday, September 5, 2014 at 11:29 AM

To: Dale Matson <dematson@comcast.net>

Cc: NPS SEKI Interpretation <seki_interpretation@nps.gov>

Subject: Fwd: From NPS.gov: Deer with two tracking collars

Mr. Matson,

Each radio collar serves a different purpose--one is a GPS (Global Positioning System) collar and the other is a VHF (Very High Frequency) collar.  The GPS collars collect spatial data through the satellite system, which is used to study space use and migration patterns.  These collars have a relatively short lifespan, lasting only a year or two.  The VHF collars have the advantage of a much longer battery life, lasting several years, but they do not collect any data themselves.  Their primary purpose is to indicate to a remote observer, who can listen to the signal produced by the collar with a receiver (similar to listening to the radio) whether the deer remains alive or not.  The VHF collars have a tip-switch in them with a ball-bearing that rolls back and forth.  If that ball-bearing stops moving, the signal transmitted by the collar changes, indicating that the collar is no longer moving.  Researchers can then locate the collar to determine whether it simply came off the animal or if the animal is dead.

These deer were originally radio-collared by the California Department of Fish and Wildlife in the Owens Valley, but their annual migration brings them upslope into Sequoia and Kings Canyon National Parks.

Sincerely,

Daniel Gammons

Wildlife Biologist

Sequoia and Kings Canyon National Parks

47050 Generals Highway

Three Rivers, CA 93271

(559) 565-3124

daniel_gammons@nps.gov

Daniel,

I appreciate the prompt reply and the rationale for the two collars. It seems to me that if the deer migrate that far, the VHF would no longer reach the remote observer. Additionally, I would suggest (and hope the technology is available) that when the GPS collar is no longer functional that the collars could have an 'on board' mechanism to release the collar from the neck of the deer. I am not a member of an animal rights group but believe scientific investigation should be as humane as possible. I have attached a photograph of the deer.

Thanks,

Dale Matson

Mr. Matson,

You are correct in that there is a limited distance at which VHF signals can be detected remotely.  This is overcome by listening for signals from aircraft.  At several thousand feet in elevation above the signal, it can be detected from many miles away.  The GPS collars are programmed to be automatically released after 1 year of data collection or just before the battery dies, whichever comes first. 

Thanks very much for the photograph.  Out of about 100 deer that were radio-collared last spring, only 5 received both VHF and GPS collars.  In a way, you were lucky to see one.  The reason only a small number received GPS collars is because since deer travel in social groups, fine scale location data will be quite similar between animals, while survival rates will vary (which is why all of them have VHF collars).

Sincerely,

Daniel Gammons

Wildlife Biologist

Sequoia and Kings Canyon National Parks

47050 Generals Highway

Three Rivers, CA 93271

(559) 565-3124

daniel_gammons@nps.gov

Daniel,

Thanks again for your response. Your information has made me more understanding and sympathetic to the process. As someone who conducted research with humans, I needed informed consent and realize the importance of humane treatment of the subject in data gathering. Thanks for the work that you do.

Pax,

Dale Matson

Note: I appreciate the quick response I received from Daniel Gammons and his respectful willingness to explain in detail the rationale for the two collars even though it was the CDFW that installed the collars on the deer.