Seasonal and diel variation in group size among Japanese sika deer in different habitats

Abstract

In¯uence of habitat type on the group size of sika deer was analysed on the basis of 2718 individuals observed in 708 groups, in the area where deer are under pressure neither from predators nor hunters. From spring to autumn, the percentage of individuals observed in the largest groups in open woodland was higher than both in clearings and closed woodland. In early winter, the percentage of individuals aggregated in the largest groups was highest in the clearings, while in late winter, the percentage of individuals observed in the largest groups was highest in the closed woodland. Besides, the percentage of large groups observed in the morning and evening (when most of deer are active) was much higher than during daytime (when level of deer activity is lower). Changes in food availability are suggested to be a factor responsible for variation in sika deer group size in different habitats.

Influence of the density of a sika deer population on activity, habitat use, and group size

“…This was probably partly connected with the fact that it was active individuals that increased their use of the closed habitats when density was higher, because active deer formed larger groups than inactive ones (Borkowski and Furubayashi 1998b). In contrast to the results of this study, Thirgood (1996) found that in fallow deer (Dama dama), groups were larger in open habitats and smaller in closed habitats in high-density populations than in lowdensity populations.…”

“…Confirmation of the importance of food as a determinant of group size (Borkowski and Furubayashi 1998b) can be seen in the link between the intensified use of woodland habitats in January 1995 and the increase in group size within those habitats. This was probably partly connected with the fact that it was active individuals that increased their use of the closed habitats when density was higher, because active deer formed larger groups than inactive ones (Borkowski and Furubayashi 1998b).…”

“…The habitats differed considerably in food conditions (Borkowski and Furubayashi 1998b), food biomass being higher in clearings than in the other habitats and higher in open woodland than in closed woodland.…”

Population status and structure of mountain nyala in the Bale Mountains National Park, Ethiopia

“…Following Lewis & Wilson (1979), Hillman (1986), Hillman & Hillman (1987), and Borkowski & Furubayshi (1998) for the study of di¡erent animals, individuals were considered as members of the same group if the distance between them was less than …”

Variation of group size among African buffalo herds in a forest‐savanna mosaic landscape

“…Seasonal variation in group size has been observed in Japanese sika deer Cervus nippon with the largest group size during seasons when food resources were optimal (Borkowski & Furubayashi, 1998). Group size in sika deer was also large during the morning and evening periods, but the authors suggest that these are large feeding aggregations rather than groups with close links (Borkowski & Furubayashi, 1998). Similar aggregations are formed in the European roe deer Capreolus capreolus when deer feed in large open fields during the morning and evening periods (Marchal et al, 1998).…”