Abstract:
The reproductive season of white-tailed deer (Odocoileus virginianus) has been hypothesized to be aseasonal
south of about 14°–18°N latitude, where annual variation in day length is low. We tested this idea by using
camera-trap data (1,336 photographed individuals identified by age and sex) collected during 2011–2017 in
the dry tropical forest of Santa Rosa National Park, northwest Costa Rica, where wet and dry seasons are well-
defined. We identified variation in monthly occurrence of spotted deer fawns, as well as the status of antler growth
of male deer, specifically related to the very seasonal environment of the region. Year-round reproduction likely
occurs, but the rainfall pattern in the area greatly influences the relative frequency of reproductive indicators, with
most births occurring during the dry season, and a second peak occurring toward the latter part of the wet season.
We speculate that food resources are the major influence on reproductive patterns, and that variation in types and
timing of food resource availability likely account for the variation in reproductive patterns.
