Movement patterns and activity of desert-adapted lions in Namibia - March 2009

> Sampling

Deciding on the best sampling intensity when programming the GPS radio collars was difficult, because an increase in data quality (frequent fixes – as high as every 10 minutes) resulted in reduced battery life of the collar. For example, by recording position data (fixes) every 10 minutes a collar will run for 1.1 years, whereas hourly fixes will extend the battery life to 3.9 years. The primary objective for this study is to collect accurate data on the movements of lions over a time scale of 24-hours (nights). Data from Xpl-3 were examined, using a bootstrap-type analysis, for the ideal sampling intensity (Figure 1). Considering the trade-off between sampling intensity and battery life, a sampling regime of hourly fixes produced sufficient precision. Sampling frequencies of a fix every 2, 3 and 4 hours also produced good results when lions moved >15 km/night. However, when lions moved short distances (<10 km/night) lower sampling regimes produced erroneous results.

Figure 1. The accuracy of calculating distances moved per night (24-hours) using various frequencies of location data (fixes) recorded by a GPS radio collar.

> Activity Patterns
> Distances
> Home Ranges
> Movement Patterns
>>>Time Frequencies
>>>Spider Analysis
>>>Circular Statistics
>>>Quarter Degree Squares