The transmitter collars are equipped with two perpendicularly positioned acceleration sensors that register the movement of the collar and, therefore, of the animal. This way, the respective x and y values for movement along the horizontal and vertical axes are recorded. Acceleration is metered continuously with 6-8 measurements per second. These values are accumulated over a five-minute period and an average is calculated. The average values are stored in the collar and are extracted upon its retrieval.
The data can be used to illustrate and evaluate activity rhythms. It is also possible to identify the times of day during which an animal is active or inactive
The Figure “Daily activity of Milan without a kill” shows the behaviour of the male lynx, Milan, on 17 April 2005. He did not have a successful kill that day and, therefore, had to hunt. The lynx was repeatedly active all day. In his search for prey, he prowled through his hunting range. Especially during the second half of the night, between 0:00 and 7:00, Milan was almost constantly on his feet. During the day, phases of activity alternated with short phases of resting. He rested for a longer period between 18:40 and 22:10.Milan’s behaviour is completely different on days that he has had a successful kill, as for example, on 21 April 2005, when he had killed a roebuck (Figure: Daily activity of Milan with a kill). On a full stomach, he can afford to rest for almost an entire day. He was only active between 14:00 and 19:50 when he was probably eating his prey.
In order to obtain even more precise information on the behaviour of the animals, the collars were used to carry out additional experiments. These have led us to the conclusion that it is also possible to use activity data to identify certain types of behaviour.
The values reveal, for example, whether an animal has been running, resting or eating. Allocation of the activity data to specific behavioural patterns is possible for the three species, lynx, roe deer, and red deer. Only red deer demonstrate behavioural patterns of a duration long enough for the five-minute intervals to accurately depict the animal’s actual behaviour. Interpretation of the actual behavioural patterns of lynx and roe deer is more difficult. Both species alter their behaviour within the five-minute intervals, thereby producing so-called mixed intervals. This means, for example, that while a lynx is running, the animal will repeatedly stand still, lie down for a minute, get up, and start running again.
With this tool it is now possible to attend to some unanswered questions, for example: how much time does a roe deer spend eating every day, how long does a lynx rest, what does a red deer do and when?
