Sika Spiker Satellite Radio Tracking Study

Study Brief – Young Sika Stag Dispersal                                                                  

This study brief outlines a radio tracking research project into the dispersal behaviours of young Sika stags to be conducted on private land in the central North Island of New Zealand.

Kaupapa (“Key Outcome”)

Long-term sustainability is at the heart of the study.  The central North Island Sika herd is an iconic deer hunting resource in New Zealand.  Our Sika trophies are some of the best to be found anywhere in the world and the wider Sika herd generates $18 Million in economic activity per annum.  Since they were liberated on Poronui in January 1905, Sika have expanded their range to cover over 9,000km².  However, as a highly efficient forest forager, Sika have also had an impact on forest health in some habitats. 

Active management is therefore, increasingly important to the long-term sustainability of a quality, trophy, Sika hunting resource.  Better understanding the herd is critical to these outcomes. Understanding Sika stag behaviour is at the heart of maximising trophy production.

Background

A Sika stag radio tracking study was undertaken on Poronui between 2009 and 2013.  Another radio tracking study of both Sika hinds and stags was conducted in the Kaweka Ranges in 2010-11.  These studies provided useful data on the movement and habitat utilisation made of the central North Island landscape by Sika deer.  The Poronui study followed seven mature stags for a minimum of 24 months.  The secondary aspect of that study, to understand dispersal behaviours in young stags, was less successful, with only four stags followed for a minimum of 24 months.  Of these, only one dispersed (~14km from collaring).  Of 16 stags collared in the Kaweka study, only one young stag dispersed (~17 km from collaring).

Understanding dispersal behaviours in sub-adult stags will provide valuable information on if, when and how far, Sika stags move from their natal (birth) territories.  Such information will help understand the ‘flow’ of what is a ‘renewable’ and highly valued Sika stag resource across the central North Island landscape. This resource is critical to many landowners, driving hunting revenue during the all-important ‘roar’ period.

The Proposal

To catch and radio collar a minimum of 10 (preferably 20) young stags from within their natal family groups with GPS Satellite tracking collars and to follow them for a minimum of 3 years.  This will capture data on what proportion, when and how far young Sika stags disperse from their natal territories.    GPS Satellite Collars will also be continuously monitored, via daily automatic internet downloads, to allow close to real time tracking of individual stags, increasing cost effectiveness of data collection in remote (back country) habitat.   All collars will be fitted with manual tracking and mortality functions to allow detection and recovery as a result of death or collar drops.

Where?

Supportive landowners are critical to the study but fortunately, there are a number who are willing and able to support he study. The vulnerability of young stags to harvest makes their protection an extremely important issue in terms of maximising data from collared animals.  Poor survival would severely limit the value of any data collected.  Ideally, a number of animals should be collared in different locations to provide diversity of data on both front country and back country habitats, and to reduce risk to the sample. 

Similar research on Whitetail deer in North America suggests herd density and structure in the population studied has a significant effect on yearling buck dispersal patterns.  A range of study locations with different habitat and herd management strategies will, therefore, provide the most robust, transferrable data.

Typical family group with target young (1+ year) stag present. Photo: Jamie Fairbairn

Personnel

The project will be co-ordinated and managed by the Sika Foundation.  The Foundation has built up close relationships with many landowners, potential sponsors, helicopter and fixed wing operators and the local hunting community.  Manual tracking support would only occur at the discretion of sponsors and landowners, as required. Deer will be captured by a local Helicopter crew who are experienced at Sika deer capture and collaring.

Landowner Inputs

Private landowners would need to host the study which will require reasonable, notified access for 12 months of the year, at times that were compatible with other activities on the property.   Maximum opportunity will be made to allow sponsors and land-owners to participate throughout the study.

Indicative Budget  

Each stag would be fitted with an Iridium GPS Satellite Tracking Collar (AU$2,300 – NZ$2,550 per unit) and would cost an estimated NZ$2,000 to capture [1.0 hr helicopter time (Hughes 500)] to become a functioning part of the study.   Ongoing satellite rental tracking costs are NZ$350 per collar per year.  Collars would collect location data eight times per day and download the previous day’s eight locations, once per day.

Each collar would also be fitted with 160MHz frequency transmitter to allow manual tracking.  Each collar would have a mortality function that would activate if the collar was immobile for more than 24hrs. The last known location would be assessed from the satellite data and the stag/collar located from that location via manual tracking.

Costings:

10 x Iridium GPS Satellite Tracking Collars @ NZ$2,550$ 25,500
Freight (Australia to NZ)$ 180
10 x stag captures to fit collars @NZ$2,000 $ 20,000
10 x Satellite Rental @ NZ$460 per collar pa (3 years) $ 13,800  
Total for minimum 10 animals over 3 years $ 59,480 +GST
Total costs to be sought per stag (over 3 years) $ 6,000 + GST

Overall Project Management: Estimate 100 hrs per annum covered by Sika Foundation.

The minimum number of stags is ten.  If more sponsorship is available, the more stags will be able to be in the sample.

Data Availability & Reporting

All GPS track logs will be carefully managed and will only be available via password.  Landowners and sponsors would have full access to all material for ‘their’ animals and/or on their land, for their own management and/or promotional purposes.

It is envisaged that the findings of the study will be widely available to help improve the understanding of Sika Stag movements, sustainable Sika Trophy development and management, among the wider Sika hunting community and landowners within the central North Island.

A full report will be prepared within 12 months of the completion of the study for appropriate publication.

How yo can support this project

If you, your business, or a syndicate of interested hunters would like to sponsor the study with a collar, please get in touch with us by emailing – mike@sikafoundation.co.nz. If you want to make a donation large or small to support this project, you can do so via bank account number 06 0433 0635669 01.

Invoices and receipts can be issued for donation/tax purposes as the Sika Foundation Conservation Trust is a registered charity. For more details, please contact Mike via email.