Research Projects

Hume Deer Herd Radio Telemetry Study
Tim Kroeker, Ca. Dept. of Fish & Game Wildlife Biologist

This report summarizes the progress of the Hume Herd Radio Telemetry Study from the first capture effort in February 2007 through June of 2010.  The Hume Deer herd is located in eastern Fresno and Tulare County.  The purpose of the project is to capture and outfit adult female deer with telemetry collars including those capable of logging GPS data points.  The data collected from this study should help define important migration corridors, holding areas and other key use areas for the Hume Deer Herd.  Further the study should provide information leading to more accurate population censuses.

Observations of the deer participating in this study has increased our understanding of deer movement for this area including changes in the way deer use the Kings River’s southern watershed, compared to observations from approximately 50 years ago when habitat and key areas for this herd were initially described.   

The Department’s partners in this project are California Deer Association which provided funds for GPS collars and VHF collars and the Mule Deer Foundation which provided funds for VHF fawn collars.

Data collected during this study is being examined and a complete report defining and describing known deer concentration areas as well as migration corridors, key winter, transitional and fawning/summer habitat is being prepared.

Methods

Clover Traps and Free Range Darting were the capture methods used.  The Clover Traps we utilized were designed to be collapsed on top of the captured deer thus providing a greater measure of safety to both the deer and Department of Fish and Game staff.  The Clover traps were open for a total of 143 trap nights during the winter and spring of 2007 and 45 trap nights in the winter of 2007-2008.  Trap design flaws caused some loss of opportunity on part of the 143 trap nights.  Because of the nature of the failures it is difficult to quantify how much opportunity was lost.  Failures included; trap gates only partially closing allowing deer to escape, birds landing on trip lines and rat trap trigger device and hail or heavy rain tripping traps.  The gates were modified allowing smoother operations, the rat traps were also modified to act more reliably as trigger mechanisms.  No failures were observed during the latter 45 trap nights.      

For chemical restraint we used Pnue-Dart projectors and 2cc darts.  The dosage we used was 125 mg of Telazol and 75 mg of Xylazine, the Xylazine was reversed with Tolazoline. 

Processing included taking a complete set of measurements, as well as blood samples.

Results

Clover Trapping

The Clover traps were used in the area around Pine Ridge and McKenzie Ridge.  A total of ten captures were made in Clover traps.  Four of these deer were fawns captured prior to our acquisition of fawn collars which were processed ear tagged and released.  One was a recapture of an already telemetry equipped doe.  Because Clover traps require a considerable amount of time to repair, place and monitor, and because they were only successful under limited conditions they were not used for captures during the third year of the study.

Free Range Darting

Attempts to dart deer were made throughout the known and suspected winter range of this herd.  A total of eighteen captures were made by free range darting.  Two of these were re-captures to recover collars which failed to deploy on the drop off date.

Monitoring

An attempt was made to locate the collared does approximately once every two weeks post capture.  The store on board GPS collars were programmed to fall off approximately one year after placement.  Fourteen GPS collars have been recovered to date.   

 None of the telemetry equipped deer died during the study, although an ear tag was recovered from a dead deer by National Park Staff about 5 months after the collar had dropped off.  Cause of death for that deer was believed to be from a vehicle strike, scavenging by a bear had also occurred. 

The signals of two collars were lost and those collars were not recovered.  A third GPS collar was nearly lost when the VHF beacon began transmitting at a much lower power after the drop off date.  When that collar was finally located the transmission distance was only about 100 yards line of sight.  One VHF collar fell off of a fawn and was recovered. 

Colored ear tags were applied to captured deer to allow them to be identifiable after the GPS collars fell off; fawns which were not equipped with telemetry collars were also ear tagged.  The ear tags have allowed monitoring to continue at a lower level.  Several of these deer have been observed during winter and spring deer herd composition surveys.

Preliminary Results

Attempts were made to capture deer throughout the accessible portions of historically identified winter and transitional range.   Concentrations of deer varied from historic observations.  Most captures took place where deer were more heavily concentrated on winter range.  A total of twenty one deer were equipped with collars, sixteen GPS collars and six VHF collars were placed on deer, including on one deer which was recaptured to remove its GPS collar.

The capture location map indicates where successful captures took place.  In some cases dots indicating captures overlap or indicate the local of multiple captures.   Deer were observed in very low numbers in some areas which were historically considered important wintering areas but captures there were not successful.

Data from project telemetry collars indicate that there is some overlap in summer and winter range.   Deer also migrated along previously un-identified corridors. Non-migratory deer were captured throughout much of the Hume deer herd’s historic winter range.  All deer captured west of White Deer Saddle migrated north of the Kings River for the summer.   

Recommendations

Capturing deer on the summer range of this herd should be done to fill in gaps in our telemetry data.  Deer captured on the summer range could help delineate undiscovered migration routes and wintering areas in habitats which are not accessible either due to private property constraints or weather dependent road access.