Introduction
The incorporation of Global Positioning System (GPS) units into animal telemetry collars [1] has greatly increased the potential for studying ranging behaviour of large herbivores. By enabling the collection of positional data over large areas, at any time of day or night and without disturbance to the animals, it is possible to build a complete picture of their movements throughout the year. GPS has been used in a 2-year study of the ranging behaviour of wild red deer (Cervus elaphus) stags in and around a 30,000 ha sporting estate and nature conservation area, in a mountainous region of the north-east of Scotland. The aim of the study was to provide information to assist in the management of deer and vegetation and to increase understanding of the behavioural ecology of the animals. Questions are being addressed at three different scales: (1) which areas are used by the deer at different times of year, (2) whether deer movements are influenced by disturbance from recreational walking within the estate, (3) to what extent deer movements are related to environmental factors, such as vegetation, topography and climate.

Methods
In each of 2 consecutive years, 9 GPS 1000 tracking collars (Lotek, Canada) were fitted to stags from the beginning of April to the end of January the following year. Each collar collected around 4500 records during the year, each consisting of a position fix and integrated activity measure. The collars were programmed to take fixes at 4-h intervals in year 1 and at 2-h intervals in year 2, with fixes every hour on Sundays and Wednesdays. In year 1, fixes were also taken every 15 minutes on 2 days each month, from June to November. Data were retrieved from the collars, via a remote radio link, every 3 to 4 months.

Analyses

1. Deer positions have been plotted on maps of the area [2], using GIS software [3], allowing the animals to be tracked over time. The information will be used to determine management strategies to promote the regeneration of native woodland within the estate, in line with conservation aims for the area.
   
2. Hourly totals from automated people-counters, beside popular tracks on the estate, show consistent patterns of activity within days, weeks and over the year [4]. In order to determine whether deer movements are affected by human disturbance, comparisons will be made between the distances of collared animals from these tracks during busy and less busy periods, for example Sundays and Wednesdays.
   
3. Environmental factors which determine deer movements will be investigated by comparing deer positions with GIS information on the topography [2], land cover [5] and weather data [6] for the area.

References

1. Rogers, A.R.; Anson, P. (1994). Animal-borne GPS: tracking the habitat. GPS World, 5, 20-32.
2. Ordinance Survey, Southampton, UK. Crown Copyright.
3. Arcview, ESRI, California, USA.
4. National Trust for Scotland (personal communication).
5. The Land Cover of Scotland (1988). Macaulay Land Use Research Institute, Aberdeen, UK.
6. British Atmospheric Data Centre, Chilton, UK.

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