Winter activity patterns of females in two moose populations

Abstract

Data on activity patterns of nine radio-tagged female moose (Alces alces) in an area with a high level of nutrition (Grimsö) and seven radio-tagged female moose in an area with a low level of nutrition (Furudal) are presented. The study was done during January–May in 1982–1986 at Grimsö and in 1986 in Furudal, comprising 6063 and 4136 h of recording, respectively. The character of the radio signals allowed separation of active (any kind of body motion, mainly movements) and inactive (a motionless state, mainly in lying position) bouts. The 24-h activity pattern was similar between the two areas during all winter months. Active bouts showed a polyphasic pattern with prominent peaks around sunrise and sunset. The average active time per 24-h interval varied (30–50%) through the winter months, and increased rapidly in April and May. The average length of active bouts was similar in both areas during midwinter (60–70 min) but developed more rapidly in April and May among moose at Grimsö. The moose at Furudal rested for longer periods than those at Grimsö, and in both areas bouts became shorter towards spring (around 120 min). The moose at Grimsö kept the number of bouts per 24-h interval almost unchanged throughout winter (11.0–11.9), while the number consistently increased at Furudal (9.9–12.7 bouts per 24-h interval). Differences in activity pattern are discussed in relation to food availability and overbrowsing.