To study annual and circadian activity proportion and activity allocation during the pup rearing period we analysed VHF telemetry-based data from the invasive, socially monogamous raccoon dog in North Eastern Germany. Proportions of active fixes for 26 adults indicate a mean annual activity level
of 58.3 %. There was no difference between males and females in mean annual activity or in the mean activity in each of the different seasons. A mean winter-activity level of 47.0 % ± 32.4 active fixes indicates that raccoon dogs did not hibernate; however, they became less active as the temperature decreases in winter. There were clear differences in the
proportion of active fixes observed in the biological seasons, with the
highest activity level (70.3 %) during the pup rearing period. Circadian
activity rhythm, sampled on a daily basis, indicates that raccoon
dogs were mainly crepuscular and nocturnal with a mean activity
level of 86.8 %. The mean diurnal activity level across the seasons was 32.4 %, ranging from 15.0 % in winter to 56.6 % during the pup rearing period. Allocation of active fixes for 24-h continuous observations during the first six weeks after parturition showed that males were mostly inactive, resting with the pups in the den, while females foraged to satisfy their
increased energy requirements. This point to a clear division of labour between parents, during the pup rearing period.
Bats appear regularly among the mammalian prey species of the barn owl. However, from numerous studies of owl pellets, bats are rarely represented in the prey of the barn owl and usually make up less than 1% of the prey individuals. Prey remains of the barn owl from the fortress Dömitz, south-east of Mecklenburg-Western Pomerania (Germany) were collected and analysed. A total of 2931 identifiable fragments from at least 1100 vertebrate individuals were discovered and identified. The analysis of the pellets over a four year period shows that, aside from the typical spectrum of mammalian prey (voles 34.9%, shrews 24.6 % and mice 13.8%), a relatively large proportion of prey individuals (26.6 %) were bats. From the pellet sample from 2002, Natterer’s bat Myotis nattereri were clearly the dominant prey with 79 individuals (30.2 %) followed by the common vole Microtus arvalis with 74 individuals (28.2 %). This high frequency of bats from the 2002 sample led to a total percentage of bats of almost 39 % and bats were clearly dominant over other potential prey groups. The frequency of bats in all samples is much higher than in all other known studies of barn owl pellet samples in a comparable volume. Our results show that Tyto alba is an opportunistic but no selective hunter of bats.
In the abandoned quarry of San Carlos (Ibiza, Balearics) prey remains of the barn owl were collected. A total of 6,977 identifiable bone remains from 2,767 individuals of mammals, birds, reptiles and amphibians was found. The spectrum of mammals clearly shows two main prey groups: mice (Mus domesticus, M. spretus : 39.4 %) and shrews (Crocidura russula, C. suaveolens : 38.4 %). Voles, which in continental Europe are the owl’s most numerous prey, are absent on Ibiza; these were replaced by mice and shrews. The record of the Pityusic wall lizard Podarcis pityusensis in the prey remains (0.5%) is remarkable. Obviously, the periods of activity of lizard and barn owl do not ordinarily overlap. One possible explanation might be that due to low prey density, Tyto alba probably starts hunting earlier during summer with its shorter nights. A skull of the European free-tailed bat (Tadarida teniotis) was recorded from the sediment, definitely confirming this species for the first time on Ibiza.