Project Summary

Role of Deer Behavior in the Transmission of Chronic Wasting Disease across a South Central Wisconsin Landscape

Principle Investigator(s):
Nancy E. Matthews
U.S. Department of Agriculture, Agricultural Research Service
Completion Date:
May 2003



The stated objectives for this work were: 

  1. Determine the daily movement patterns and amount of temporal and spatial overlap of does, within and among social groups of deer; 
  2. Assess potential rates of contact among does by season; 
  3. Determine the seasonal movements and dispersal rates of all sex and age classes of deer;
  4. Determine the spatial and temporal overlap of deer with domestic livestock; 
  5. Compare movements and behavior of deer known to be infected with CWD to those known to be disease free.

Deer Home Range Sizes. Deer were trapped on two main study areas within the Eradication Zone.  Traps were set up in November of 2003 and run through March of 2004. They were re-opened in November of 2004. The data reflected in this report included deer captured during the December 2003 and early 2004 trapping period.

Social Group Membership. Membership to social groups was determined by preliminary associations among females.  

Deer Movements. During the period of this study deer made a number of exploratory movements. 

Deer overlap with cattle pastures. Based on the locations of the radio collared deer, cattle pastures potentially used by these deer were identified. Home ranges of deer were plotted to determine the amount of overlap, while the number of relocations within close proximity to the pastures was determined. 

Interviews with land owners. Interviews with the land owners grazing the cattle reveal a variety of grazing practices on the identified pastures. 


Deer Home Range Sizes. Home ranges were calculated during the parturition period (May 20 to June 30), non-parturition (July 1 to October 9), and rut (October 10-December 31). Home ranges were plotted on to digital ortho photo quads for 23 deer, scattered across both study areas for each of these time periods. Average home range size for adult females during parturition was 0.16 sq. mi. while the average for yearling females was 0.12. Adult male home range sizes were over twice as large as adult females, while yearling males were nearly identical to yearling females.

During the non-parturition period, home range sizes did not change dramatically from those during the parturition period for adult females and yearling males. Yearling females enlarged their home ranges while adult males apparently decreased the size of theirs.

During the rut, yearling and adult females maintained a home range size consistent with the non-parturition period; however, both yearling and adult males nearly doubled their home range sizes Despite this increase in size, the home ranges for all sex and age classes are substantially smaller than those reported in previous studies.

Social Group Membership. Clusters of deer are readily apparent across the landscape. A number of doe and fawn pairs were captured, thus verifying some members of the social group. Additional telemetry data are required before membership can be confirmed.

Deer Movements. The possibility of some migratory movements cannot be excluded; however, the mother/fawn combination that made such movements were subsequently killed by hunters before they could return to their summer range, if that was their intention. The longest exploratory movement was nearly 24 mi. This young female subsequently returned to her natal home range and has continued to stay there. Three young males appear to have dispersed; however, two were killed, thus it is impossible to determine whether these would have been true dispersal. The last yearling male (# 1106) appears to have established a new home range approximately 5 mi from its natal home range.

Deer overlap with cattle pastures. Several deer overlapped extensively with the pastures. The number of relocations directly in the cattle pastures for most deer were low; however, four deer, three adult does and one yearling doe, were relocated almost exclusively within close proximity to the pastures. These patterns were consistent throughout the summer and fall. Plots of the actual relocations of the deer during the late spring and early summer reveal the clustering and overlap among deer. 

Interviews with land owners. Rotations ranged from early spring, to three times per year. Pastures were grazed with as few as 12 to many as 75 head of cattle. All pastures contained salt licks and feeding stations, which were potential gathering sites for deer and cattle.


These results confirm the potential for deer to spend an extensive amount of time in cattle pastures. Overlap occurs in both space and time based on our results. These results also suggest that assumptions regarding deer movements and behavior must be withheld until a full analysis of the data can be completed. Based on previous studies, the general assumption was that home ranges would be significantly larger for all sex and age classes of deer. It was also assumed that males would disperse farther and, perhaps more successfully. The preliminary results of this study suggest that all deer use much smaller home range sizes in this habitat than would have otherwise been estimated. This type of “anomaly” should not be underestimated in its influence in epidemiological models predicting the spread of CWD. Further, we have virtually no evidence that males are serving as propagules via long-range dispersal at this time. However, the small sample of yearlings in our study to date does not provide a clear picture of the dispersal potential for this population. Continued monitoring of the radio-transmittered deer is necessary to better understand how behavior may influence the spread of the disease and the potential for interactions with cattle.