|Abstract or Summary
- A study of the life history, population dynamics, and ecological relationships of the Columbian white-tailed deer (Odocoileus virginiarius leucurus) was conducted on the
Washington mainland, Columbian White-tailed Deer National Wildlife Refuge during 1972-1973 to provide information for management of this endangered subspecies. A total of 18,077 observations of deer recorded during 213 morning and evening periods along two observation routes provided information concerning use of plant communities, activity, group composition, and sex and age structure. Detailed behavior observations were recorded during 25 morning
and evening periods. Vegetation on the study area was categorized into five major community groupings of rush, thistle, grass, horsetail, and forest Deer were observed most often in those communities that provided both cover and forage. Communities providing forage without cover were most used
where cover was adjacent. The population on the study area during the winter was
estimated between 200 and 230 deer or one, deer per 3.4-3.9 hectares (one deer per 8.5-9.8 acres). A buck:doe:fawn ratio of 34:100:35 was calculated for November. Average group size of deer while grazing was 2.2 animals The major classification of group size throughout, the year was of single deer. Numbers of individuals within groups were highest during winter. Overt aggression between individuals was observed infrequently. Frequency of aggressive behavior was greatest during cold weather. Bucks were always dominant over does and fawns, and does were always dominant over
fawns. Grazing was numerically the major activity observed. Deer grazed more and rested less in summer than during winter.
Copulations may occur primarily at night. Home ranges of bucks were 1arger than those of does, and home ranges of yearlings were larger than those of adults. Average home
range size of the Columbian white-tailed deer was smaller than that reported for other subspecies. Deer avoided close association with cattle and used those areas where cattle densities were lowest or where
cattle were not present. Deer showed preference for improved pasture prior to introduction of cattle for seasonal grazing.