MOOSE MODIFY BED SITES IN RESPONSE TO HIGH TEMPERATURES

Abstract

Moose (Alces alces) employ physiological and behavioral mechanisms to enable them to dissipate excess heat when ambient temperature is above the upper critical temperature of their thermoneutral zone. In this note, we describe 2 cases where GPS radio-collared female moose modified summer bed sites as a potential thermoregulatory response to high temperatures. The first case occurred on 18 - 21 July 2011 when ambient temperatures averaged 25 °C (8 °C above the upper critical temperature of moose) and reached 32 °C and 96% relative humidity. Based on field observations of the bed site immediately after use, the moose cleared litter and duff to expose 3 m² of mineral soil under a closed-canopy balsam fir (Abies balsamea) stand. The moose spent 64% of the time bedded during a 4-day event, with ≤11 individual bedding events in the same bed site. A second case was observed on 5 July 2013 during similar weather conditions (29 °C and 70% relative humidity) when a different moose cleared a bed site and used it continuously for 10 hours.