Klaus M. Scheibe

Seasonal Variation of Diurnal and Ultradian Rhythms in Red Deer

To describe the normal rhythmic behavioural patterns and to test procedures for the detection of short-time disturbances, 4 red deer were studied in 2 quasi-natural enclosures. Activity and feeding were recorded by means of the storage-telemetrysystem ETHOSYS®. Daily and monthly mean values, power spectra and ‘Degrees of Functional Coupling’ (DFC) were calculated. DFC were applied to measure stability and harmonic synchronisation between ultradian rhythms and the 24-hours period. The general patterns of activity and feeding were nearly identical in all animals and closely related to photoperiod change. Levels of total activity and feeding were lowest in winter and highest in summer. In winter highest activity was generally observed in daylight hours and shifted gradually to dark hours in summer. Spectral analysis of activity and feeding revealed a time pattern in which ultradian components, between 4.8 and 12 hrs in period length, mostly exceeded the diurnal rhythm power. Compared to winter higher frequencies were found in activity and feeding in spring, summer and autumn. During such periods up to 8 strong bouts of activity per day (3-hrs rhythm) were observed. These rhythmic patterns are discussed in the context of red deer feeding strategy. Short-term disturbances by humans and changing feeding conditions resulted in lowered DFCs. Time pattern analysis of long-term and continuously measured behavioural parameters proved to be an appropriate approach for observing general living conditions and for detecting disturbances.

Annual Rhythm of Body Weight in Przewalski Horses (Equus ferus przewalskii)

The live-weight of female Przewalski horses in a semi-natural reserve has been recorded continuously over 6 years by means of an automatic weighing machine and automatic identification. Data were tested for cyclic as well as for linear trend effects and a mathematical model was developed. A clear annual rhythm of live-weight with the maximum in October was demonstrated. During the first 2 years of recording, the level of the annual rhythm was constant but, thereafter, different individual trends were found. Those individuals showing a steeply rising trend suffered from laminitis after three annual cycles. The periods of rising body weight corresponded to unusual mild winters. Animals newly introduced into the reserve from zoos showed a rise in their body weight in an adaptation phase. Furthermore, there was evidence for a phase adjustment of the annual rhythm. The results are discussed against a background of the theory of annual rhythms, and can be used as a basis for seasonal variations of feeding in zoos and for a re-evaluation of recommendations for population density in similar reserves. For reintroductions as well as for a transfer from zoos to semi-natural reserves, a longer adaptation phase is recommended.

Long-term automatic video recording as a tool for analysing the time patterns of utilisation of predefined locations by wild animals

The design and application of automatic video recording systems for wild animals are described. Such systems enable continuous, long-time and repercussion-free surveillance of selected areas in the field. The performance characteristics of a conventional VHS video-tape system are compared to a digital video recording system. The recordings were used to develop daily and annual plots of occurrence for the different species and to display the preferences for darkness, twilight and light phase by the different species over the year. Absolute utilisation frequency as well as relative species composition can be obtained and compared between seasons or different places. The videos also were analysed for time budgets of basic behaviour patterns like feeding, walking, observing, social interaction, flight and comfort behaviour. Automatic video technique is a highly convenient tool for systematic long-term field research on occurrence of wild animal species, daily and annual activity rhythms, behaviour and area utilisation. Such systems can be applied especially to record animals at clearings, feeding or bait places, water sources, salt licks or traps.

Characteristic activity patterns of female mouflons (Ovis orientalis musimon) in the lambing period

Abstract We analysed the activity pattern of wild mouflon sheep (Ovis orientalis musimon) in the lambing season for 2 consecutive years. The activity data was recorded automatically by the storage-telemetry-system, ETHOSYS. The animals were equipped with electronic collars of about 300 g, which continuously sampled behaviour in time intervals of 30 min over 50 days. Lambing was accompanied by decreased daily activity budgets of 3–5 consecutive days. The sequence of daily activity budgets around parturition were compared with other periods of lower activity using discriminant analysis. Birth patterns were found to differ significantly in width, depth and shape from normal fluctuations in daily activity. Calculating the discriminant function from the 1995 data, we accurately predicted the 1996 minima in activity caused by lambing. The jackknife method, providing an even more precise misclassification rate, was 93% accurate. Changes in activity patterns and space utilization in the period peri partum in the wild are discussed in contrast to what happens for animals at pasture or in enclosures.

An activity-data-logger for monitoring free-ranging animals

A small (16 cm × 15 cm × 21 cm) solar powered activity-data-logger (ADL) has been developed as a suitable instrument for recording the presence and movements of free-ranging animals. Locomotor activity is recorded by a passive infrared detector (PID). At fixed intervals the signals picked up by the PID are condensed automatically and stored in the ADL. This database can be transferred for further use onto a lap-top or PC. The ADL can store information for up to 80 days and thereafter this information has to be tranferred in order to use the ADL further. A solar-generated accumulator serves as the power supply. The activity of mouflons (Ovis ammon musimon) at a saltlick was recorded between June and September 1993. The ADLs performance was validated by video cameras. We monitored the number of sheep coming into a certain area and the time they stayed on film and this correlated with the findings using the ADL. The daily pattern of the mouflons may be characterised as polymodal with activity periods correlated with dawn and dusk. With decreasing day length in autumn, an additional activity period appeared after midnight. Contrary to popular belief, we registered high proportions of nocturnal activity in every month of the study. Artificial feeding at a particular time of day seems to mask the general influence of the light-dark-cycle as the natural ‘Zeitgeber’.

Variation of the phase of the 24-h activity period in different large herbivore species under European and African conditions

The variation of daily rhythms were analysed in relation to environmental factors. Activity phases were determined for Przewalski horses (Equus ferus przewalskii), feral domestic horses (Equus caballus), and mouflon (Ovis orientalis musimon) in Europe under semi-natural conditions by storage telemetry (ETHOSYS®) and compared to samples from plain zebra (Equus burchelli) and blesbok (Damaliscus dorcas phillipsi) in South African reserves. The activity phase of Przewalski horses was about 16 h in the afternoon but delayed during the summer months; feral horses showed similar phases with lower variation. Mouflons had phases of about 14 h, delayed until 20 h during summer. Zebra showed activity phases after midnight, in the morning, afternoon, and in the evening, but never around noon. The activity phases of blesbok were found at all times of the day. The high variation under African conditions is discussed as resulting from masking by temperature, drought and predation pressure.