United States 

Department of 

Agriculture Drive-Line Census for Deer I 

Forest Service Within Fenced Enclosures 

Northeastern Forest 

Experiment Station 

Research Paper NE-643 David S. decalesta 

Gary W. Witmer 
Abstract 

Methodology is presented for conducting drive-line counts to obtain absolute 

numbers of deer within fairly small (~560 ha) areas. Planning and layout of the 

drive and the organization of persons who make up the drive-line teams are 

discussed. Procedures for maintaining proper spacing and alignment of drivers 

are described. On a drive of a 5.7-km2 estate enclosed by a 2.5-m-tall deer fence 

in northwest Pennsylvania, numbers of deer (78) were within one of an estimate 

derived from a standard deer pellet-group count. The key elements of a 

successful drive are organization and communication before and during the drive. 

The Authors 

DAVID S. DECALESTA is a research wildlife biologist with the Northeastern 

Forest Experiment Station's Forestry Sciences Laboratory at Warren, Pa. Before 

joining the USDA Forest Service in 1986, he was engaged in wildlife research at 

North Carolina State and Oregon State Universities. He received a B.A. degree in 

psychology from Dartmouth College and M.S. and Ph.D. degrees in wildlife 

ecology from Colorado State University. 

GARY W. WITMER is a member of the Wildlife Technology Program at The 

Pennsylvania State University's DuBois Campus at DuBois, Pa. 

Manuscript received for publication 24 July 1990 

Northeastern Forest Experiment Station 

5 Radnor Corporate Center 

100 Matsonford Road, Suite 200 

P.O. Box 6775 

Radnor, Pennsylvania 19087 

September 1990 
Introduction Study Area and Methods 

Early estimates (1800's) of deer Odocoileus sp. numbers in 

North America were obtained by driving deer past shooters 

and counting the numbers of deer killed (Leopold 1933). 

This technique was refined for use by the Civilian 

Conservation Corps in the Allegheny National Forest in the 

1930's (McCain 1939) and was published as a Forest 

Service technique in 1940 (USDA For. Serv. 1940). As 

developed, the technique was used to census free-ranging 

deer on fairly small tracts of land (5260 ha) by driving deer 

past counters stationed on boundary lines of areas being 

censused (Hosely 1956; Overton 1971). A modification 

(Morse 1943) replaced counters on boundary lines with 

snow-covered open lanes: deer were driven past these 

lanes by drivers on line. Counts of tracks on the lanes and 

deer passing back through the drive line constituted the 

estimate of deer numbers within the area censused. 

The drive census was plagued by a number of problems. It 

was time consuming and costly. Only small areas could be 

censused and a large number of personnel was required. 

Terrain must be fairly level and undissected, and deer must 

be highly visible, requiring little understory vegetation 

and/or snow cover (McCain 1939; Ruff 1939; Morse 1943; 

Trippensee 1948; Hunter and Taylor 1956). 

Consequently, it was discontinued as a general method for 

estimating numbers of free-ranging deer and replaced by 

other techniques, such as pellet-group counts and aerial 

surveys (Gill et al. 1983). However, the utility of the drivecensus technique for counting deer within enclosures was 

recognized decades ago (O'Roke and Hamerstrom 1948). It 

continues to be used in that setting (McCullough 1979) and 

as a tool to "prove" to disbelievers that there are still large 

numbers of deer in the woods (Jenkins and Bartlett 1959). 

For the past 2 years we have been involved in a project on 

a private estate near Bradford in McKean County, Pennsylvania, 

to demonstrate that managing the density of white-tailed 

deer (0. virginianus) can enhance hardwood regeneration. 

Deer density was being estimated by pellet-group counts. 

The managers of the estate did not want to manage deer 

numbers based solely on such counts, so we conducted a 

drive census on the estate on November 4, 1988. 

In our search of the literature for guidelines on conducting 

deer drives, we found little specific current information, as 

have others (Davis and Winstead 1980; Riney 1982; Boyd et 

al. 1986), and had to model our procedure on old and 

sketchy reports. In this paper we describe the procedure 

used for conducting a drive census of deer within a deerproof enclosure, and compare the results of our drive 

census with a population estimate derived from 

pellet-group counts. 

The drive was conducted on the 5.7-km2 Glendorn Estate, 

approximately 8 km southwest of Bradford, PA (Fig. 1). The 

estate is enclosed by a 2.5-m-tall deer fence constructed of 

woven-wire livestock fence material and supported on 3-mtall steel posts driven 0.6 m into the ground. Roughly 

rectangular, the estate is approximately 2,845 m long and 

2,000 m wide. A small valley runs through the middle of the 

long axis of the estate, and two ridges rise above on either 

side. Elevation ranges from 487 to 610 m. The estate is 

moderately dissected and contains three small ponds, the 

largest of which covers approximately 3.1 ha. A system of 

paved and graveled roads and trails allows easy access to 

all areas on the estate. 

Approximately 90 percent of the estate is heavily wooded 

with second-growth northern hardwoods, including red and 

sugar maples (Acer rubrum and A. saccharurn), black cherry 

(Prunus serotina), American beech (Fagus grandifolia), white 

ash (Fraxinus arnericana), birch (Betula spp.), eastern 

hemlock (Tsuga canadensis), and white pinelpinus strobis). 

There is relatively little understory growth, and visibility 

within 1.5 m of the ground is excellent. 

Designing the Drive Line 

The drive line was divided into 10 sectors, parallel to the 

long axis of the estate. Each sector was approximately 

200 m wide. The drive was conducted from the west fence 

to the east fence (Fig. 1). A critical factor in obtaining as 

complete a count as possible was ensuring that persons on 

the drive line were sufficiently close to one another that they 

could see each other and any deer passing between them 

(Hosely 1956; McCullough 1979). On the basis of trial and 

error in the field, we determined this distance to be about 

22 m, requiring nine drivers per sector. Hosely (1936) 

recommended 40 m between drivers and Trippensee (1948) 

recommended 15 to 30 m. 

Communications among persons on the drive line are 

critical to maintaining the integrity of the line (McCain 1939; 

Hosely 1956). A sector leader was assigned to each sector 

(Hosely 1956; McCullough 1979) to control movements of 

drivers within the sector. Sector leaders maintained radio 

contact with the drive leader via hand-held radios and 

communicated the need for the drive line to stop while their 

sectors negotiated obstacles. Communication between the 

drive leader and all persons on the drive line was achieved 

with a hand-held air horn. One long blast on the horn 

signaled "stop" to all drivers, three short blasts signaled 

"start". 

Another critical factor is keeping the drive line straight 

(McCullough 1979). To ensure that the drive line was 
Figure 1 .-Map of Glendorn Estate, detailing location of flagged transect routes, string 

lines, starting and stopping lines, and roads and trails. 

properly aligned and with sufficient spacing between 

adjacent drivers, the starting point for the drive was the 

west fenceline. Blue 7.5-by-1 2.5-cm cards were stapled to 

the fenceline and labeled to mark sector boundaries. Pink 

cards denoted starting locations of drivers in each sector.< 

Sector numbers were printed on the blue cards, and 

numbers for individual drivers were printed on the pink 

cards. 

To counter the tendency of the drive line to wander, we 

placed two lines of string perpendicular to the drive line 

across the entire width of the estate at approximately onethird and two-thirds of the distance between start and finish 

(Fig. 1). Hosely (1936) and McCullough (1979) used paint 

spots on trees to mark places for drive lines to realign. All 

drivers were instructed to stop at each string line and to 

wait for a signal (three blasts on the air horn) before they 

resumed the drive. This procedure ensured that the drive 

line was realigned a minimum of two times. 

Obstacles (ponds, windfalls, or steep terrain) can slow the 

progress of a portion of the drive line, resultinn in large 

gaps between drivers through which deer canslip 

- 

undetected (McCullough 1979). To minimize this problem, 

sector leaders reported obstacles to the drive leader, who 

then halted the entire drive line by sounding the air horn. 

The drive was restarted when the sector leader reported 

that his drivers had cleared the obstacle.. 

It is important that drivers be spaced properly during the 

drive (Hosely 1956). Drivers were instructed to attempt to 

maintain a distance of 20 to 22 m between themselves and 

adjacent drivers. Sector leaders wore blaze yellow caps to 

increase their visibility, and drivers were instructed to 

attempt to stay abreast of the sector leader. A flagged route 

was established for each sector leader the day before the 

drive by placing surveyor's flagging on trees and bushes at 

intervals of 10 to 20 m along parallel compass lines 

extending from the west to east fences. 

Three counters walked parallel to, and slightly ahead of, the 

drive line and outside the fence on each side. These 
counters were used to count any deer observed exiting the 

estate by leaping over, climbing under, or bursting through 

the side fences. Twenty counters were spaced along the 

east fenceline (finish line) to count any deer forced by the 

drive line to jump over, climb under, or burst through the 

end fence. Several counters on the east fenceline were 

equipped with hand-held radios, and were instructed to 

contact the drive leader to slow the drive line if the deer 

were running into the fence or in other ways injuring 

themselves, or were escaping. 

Timing of the drive was important to ensure optimal 

conditions for observing deer. We scheduled the drive a 

month after the time of leaf drop when there often is light 

snow cover. 

Communications 

Success of a drive requires that all drivers understand 

exactly what they are to do (McCain 1939; Hosely 1956; 

O'Roke and Hamerstrom 1948). Two months before the 

drive, candidate drivers were solicited by mail, forming an 

initial pool of drivers. This pool was pared to approximately 

120 persons who were organized into sector teams 

according to their home location andlor affiliation (several 

sportsman clubs participated in the drive). A sector leader 

was chosen from each sector team. Each driver was mailed 

an informational brochure that provided details on the drive, 

expectations of drivers, appropriate clothing, and the name 

and telephone number of sector members and the sector 

leader. Drivers in respective sectors were encouraged to 

contact each other and car pool to the estate. 

Drivers for each sector were assigned a meeting point on 

the estate. Once assembled, all sectors met together for a 

briefing just before the drive. Assembling drivers by sectors 

allowed easy verification that all were present. 

Conducting the Drive 

Participants were briefed at the meeting location, then trucked 

by sectors to the west fenceline where drivers located their 

assigned starting positions. Sector leaders called to the 

drive leader when all of the drivers in their sections were in 

position. The drive began when all sectors had reported. 

Drivers were instructed to count only deer that passed 

between themselves and the driver to their immediate right 

(Hosely .l956; McCullough 1979). Drivers recorded deer that 

either passed back through the line or passed forward from 

behind the line. Deer recorded passing in both directions 

were totaled separately. At the end of the drive, the count of 

deer was obtained by subtracting the sum of those passing 

forward from the sum of those passing back through the 

line. 

The estate narrowed from 2,000 to about 1,600 m two-thirds 

of the way between west and east fencelines. Rather than 

shorten the distance between themselves and adjacent 

drivers, those drivers forced into the north and south 

fencelines at the constriction point simply walked along the 

fenceline until they reached the east fenceline. 

As each sector completed the drive, sector leaders 

collected data forms from drivers and led them back to the 

meeting point where they waited for a final debriefing. The 

drive leader collected all data forms from sector leaders at 

the meeting point, quickly tabulated results, and reported 

them to drive participants. 

Deer Numbers from Drive vs. Pellet-Group Counts 

Pellet groups were counted along eight transect lines (3 m 

wide) that traversed the width of the estate. Earlier work 

(J. Jordan and N. Tilghman, USDA Forest Service, Warren, 

PA, pers. comun.) suggested that deer in northwestern 

Pennsylvania defecate an average of 13.5 times daily. An 

estimate of the number of deer on the estate was obtained 

using this value in a standard procedure for counting pellet 

groups (Overton 1971). Estate managers had requested the 

drive so that they could calculate how many deer to harvest 

to achieve a deer density compatible with successful 

regeneration of hardwoods, i.e., about 6.5 deerlkm2 

(Behrend et al. 1970; Tilghman 1989). Managers harvested 

38 deer from the estate in the months following the drive. 

The number of deer counted in the drive, minus deer 

harvested, was compared to an-estimate of deer derived 

from a pellet-group count conducted the following April. 

Results 

Seventy-eight deer were counted by 11 6 drivers and 

counters. Deer passed through the line of drivers singly and 

in groups. Some drivers counted only a single deer, others 

counted as many as 5 to 10, and many drivers never saw a 

deer during the 2% hour drive. Light rainlhail fell during the 

first half hour of the drive, and there was no snow cover. 

As the drive line approached within 300 m of the east 

fenceline, observers on the fence reported that several 

groups of deer were dashing back and forth in front of the 

fence and that one deer had broken its neck leaping into 

the fence. The drive line was stopped, then allowed to 

proceed at about half the original speed. This tactic was 

effective as the remaining deer bolted back through the 

drive line in two large groups of 10 to 15. 

The pellet-group technique provided an estimate of 39 deer 

present on the estate in April, which was in close agreement 

with the number presumably remaining after harvest (78 

deer counted - 38 deer removed = 40 deer). 

Recommendations 

The technique for censusing deer within fenced enclosures 

seems to produce reliable estimates of deer numbers so 

long as environmental conditions allow optimal viewing. Had 

there been a thick understory or heavy rain or snowstorms, 
it is likely that drivers would have missed counting some 

deer. Lack of snow cover did not reduce visibility, but 

visibility would have been enhanced by more of a contrast 

between darker deer and a light background. 

We believe that our emphasis on communicating and 

organizing before and during the drive contributed 

materially to its success and lack of problems. The flagged 

sector-leader routes and string lines helped maintain a 

straight drive line, which, in turn, reduced the possibility of 

deer running unnoticed between drivers. 

This technique requires an investment in time and money 

for the planning sessions and mailings. A large number of 

able and committed volunteer drivers is an absolute 

requirement. Enclosures with regular boundary lines formed 

of deer-proof fencing ensure that deer remain within the 

census area. There is undoubtedly an upper limit to the size 

of enclosure that can be driven in a single day. Our results 

suggest that a distance of 5,000 m can be driven in one 

day. The width of the area driven would be determined by 

the number of drivers available. Placing string lines at 

intervals of roughly 1,000 m perpendicular to the direction 

of the drive line should allow the drive line to be realigned 

as needed. 

The close agreement between estimates of deer density 

derived by pellet-group counts and the drive census 

suggests that either can be used to estimate deer density 

within fenced enclosures. But because pellet-group counts 

require so much less time, manpower, and expense, one 

might question the use of the drive count. Also, conditions 

favorable for conducting drive censuses and pellet-group 

counts are similar (minimal understory vegetation and open, 

gentle terrain). The drive census probably should be 

reserved for locales where there are no reliable pellet-group 

defecation rates, where local conditions are not conducive 

to easily observing pellet groups (extremely dense, low 

ground cover), or where an actual count of deer is desired. 

The technique described here is not applicable everywhere 

there is a deer enclosure, but for situations similar to ours, 

with good visibility in the understory and fairly level terrrain, 

it does provide managers with a reliable estimate of deer 

numbers. 

Literature Cited 

Behrend, D. F.; Mattfeld, G. F.; Tierson, W. C.; Wiley, Ill, 

J. E. 1970. Deer density control for comprehensive 

forest management. Journal of Forestry. 68: 695-700. 

Boyd, R. J.; Cooperrider, A. Y.; Lent, P. C.; Bailey, J. A. 

1986. Ungulates. In: Cooperrider, Y. A., ed. Inventory 

and monitoring of wildlife habitat. Denver, CO: U.S. 

Department of Interior, Bureau of Land Management, 

Denver Service Center: 564-579. 

Davis, D. E.; Winstead, R. L. 1980. Estimating numbers of 

wildlife. In: Schemnitz, S. D., ed. Wildlife techniques 

manual. 4th ed. Washington, DC: The Wildlife Society: 

221-245. 

Gill, R. B.; Carpenter, L. H.; Bowden, D. C. 1983. 

Monitoring large animal populations: the Colorado 

experience. Transactions of the North American Wildlife 

Conference. 48: 330-341. 

Hosely, N. W. 1936. Forest wildlife census methods 

applicable to New England conditions. Journal of 

Forestry. 34: 467-471. 

Hosely, N. W. 1956. Management of the white-tailed deer 

in its environment. In: Taylor, W. P., ed. The deer of 

North America. Harrisburg, PA: Stackpole Co.: 187-259. 

Hunter, G. N.; Taylor, W. P. 1956. Management of the 

mule deer. In: Taylor, W. P., ed. The deer of North 

America. Harrisburg, PA: Stackpole Co.: 449-482. 

Jenkins, D. H.; Bartlett, I. H. 1959. Michigan whitetails. 

Lansing, MI: Michigan Department of Conservation. 80 p. 

Leopold, A. 1933. Game management. New York: Charles 

Scribner's Sons. 481 p. 

McCain, R. 1939. The development and use of game 

drives for determining whitetail deer populations on 

Allegheny National Forest. Transactions of the North 

American Wildlife Conference. 4: 221-230. 

McCullough, D. R. 1979. The George Reserve deer herd. 

Ann Arbor, MI: University of Michigan Press. 271 p. 

Morse, M. A. 1943. Technique for reducing man-power in 

the deer drive census. Journal of Wildlife Management. 

7: 217-223. 

O'Roke, E. C.; Hamerstrom, F. N. 1948. Productivity and 

yield of the George Reserve deer herd. Journal of 

Wildlife Management. 12: 78-86. 

Overton, W. S. 1971. Estimating numbers of animals in 

wildlife populations. In: Giles, R. H., ed. Wildlife 

management techniques. Washington, DC: The Wildlife 

Society: 403-455. 

Riney, T. 1982. Study and management of large 

mammals. New York: John Wiley & Sons. 552 p. 

Ruff, F. J. 1939. Region 8 technique of wildlife inventory. 

Transactions of the North American Wildlife Conference. 

4: 542-545. 

Tilghman, N. G. 1989. Impacts of white-tailed deer on 

forest regeneration in northwestern Pennsylvania. 

Journal of Wildlife Management. 53: 524-532. 

Trippensee, R. E. 1948. Wildlife management: upland 

game and general principles, volume I. New York: 

McGraw-Hill Book Co. 479 p. 

U.S. Department of Agriculture, Forest Service. 1940. Deer 

census drive method. Wildlife handbook. Milwaukee, 

WI: US. Department of Agriculture, Forest Service, 

North Central Region. 4 p. 
decalesta, David S.; Witmer, Gary W. 1990. Drive-line census for deer 

within fenced enclosures. Res. Pap. NE-643. Radnor, PA: US. 

Department of Agriculture, Forest Service, Northeastern Forest 

Experiment Station. 4 p. 

Methodology is presented for conducting drive-line counts to obtain 

absolute numbers of deer within fairly small (1560 ha) areas. Planning and 

layout of the drive and the organization of persons who make up the 

drive-line teams are discussed. Procedures for maintaining proper spacing 

and alignment of drivers are described. On a drive of a 5.7-km2 estate 

enclosed by a 2.5-m-tall deer fence in northwest Pennsylvania, numbers of 

deer counted (78) were within one of an estimate derived from a standard 

deer pellet-group count. The key elements of a successful drive are 

organization and communication before and during the drive. 

ODC: 1 51.2(748) 

Keywords: Census technique; Pennsylvania; white-tailed deer; population 

estimation 

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