Activity patterns and their relationship to the habitat use of mule deer (Odocoileus hemionus) in the Chihuahuan Desert, Mexico

Abstract

In desert regions, species have adapted physiologically and behaviorally to the extreme conditions of their environment, such as a lack of water and extreme temperatures. This is the case of the mule deer (Odocoileus hemionus) a species which many aspects of its relationship between behavioral ecology and habitat characteristics are unknown. The objectives of this study were: 1) to characterize the daily activity pattern of female mule deer in relationship to three behavioral patterns: resting, feeding and moving, and 2) assess the relationship between these behavioral patterns and the characteristics of the habitat. This study was conducted in the Chihuahuan Desert, where six females of mule deer were monitored using VHF radiotelemetry between 2012 and 2014. We distinguish the behavioral patterns by sensors in the collar and we quantified the number of beeps emitted per minute. Moreover, we described the daily pattern associated with these activities using Kernel density graphs and evaluated the effect of habitat variables on the frequency of resting and feeding behaviors applying a generalized linear model (GLM). We identified the location in which feeding and resting behaviors occurred, and the type of plant associations present and the percentage of area they occupied. We recorded locations over 328 days/deer. Female mule deer spent most of their time resting (63.41 %), followed by moving (21.26 %), and feeding (15.34 %). Deer movement and feeding behaviors were most frequent during the crepuscule. The temperature was the only variable that influenced resting and feeding behaviors (deviance = 4.7; d. f. = 1; P = 0.02). The estimated area used for resting was 10.35 km2, while the corresponding area for feeding was 6.45 km2, in which the plant association with dominance of Larrea tridentata, Opuntia rastrera and Fouquieria splendens was the most common. Considering the high temperatures prevailing on the region, resting most of the day likely helps deer to have an adequate thermoregulation. The time dedicated to feeding is less than the dedicated to other activities; deer may be spending more time moving than feeding due to the spatial distribution of suitable food patches, or to avoid predators. The mule deer occupy the same areas to feed and rest; however, feeding areas are smaller those used to rest, these areas have been identified in previous studies as those with the greatest use (core areas). In the plant association with greater occupation within the feeding zones, there are species reported as an essential for the deer diet; these areas are located at the foot of the hill, which gives the deer thermal protection.