Animal Census and Other Applications of Remote Sensing in 
Wildlife Management and Habitat Research in Forested Areas 
FOREST W. STEARNS?! 
The use of remote sensing techniques in census ac- 
tivities will be discussed. Possible applications of re- 
mote sensing to wildlife and wildlife habitat research 
will also be suggested. The previous papers have em- 
phasized the general principles of remote sensing 
techniques, the problems involved in such techniques, 
the need for ground truth, the unused potential of con- 
ventional aerial photography, and the great value of 
large-scale aerial photography for habitat analysis. 
WILDLIFE CENSUS OBJECTIVES 
The need for an absolute census of animals 
or birds is often questionable. Knowledge of 
population trends is probably as valuable in 
game management as knowledge of the exact 
number of individuals. However, in recent 
years pressures have developed that demand 
more and more accuracy in estimation of num- 
bers. For one thing, management based on 
numbers is somewhat more readily sold to the 
administrator and his friendly critic, the 
sportsman. Also, as management is intensified, 
management units reduced in size, kills better 
regulated, and habitat-environment interac- 
tions better understood, the need for better 
census techniques will increase. 
In research on mammals or birds and their 
habitat, it is often essential to know the num- 
ber of individuals involved to properly under- 
stand the response of both the individual and 
the population to the changes or conditions 
being measured. 
Cain, in his talk at the 4th Remote Sensing 
Symposium in 1966, summarized the demand 
for improved remote techniques for census as 
follows: 
“There is need for information on 
population size, occurrence of subpo- 
pulations, and distribution in space 
and time of individual species and as- 
sociations of different species. There 
is need for data on recruitment and 
mortality. Such inventory data are re- 
quired for fishes, birds, and mammals 
of importance to man if they are to be 
granted conservation management, 
that is, if man is to make nondeple- 
tive use of them by avoiding over- 
harvest.” 
TERRESTRIAL CENSUS METHODS 
The techniques now used for animal census 
*Formerly Plant Ecologist, North Central Forest 
Experiment Station, USDA Forest Service, Rhine- 
lander, Wisconsin, now with the University of Wiscon- 
sin-Milwaukee. 
194 
will be considered briefly. This is not a com- 
plete summary, but it will help put some of the 
more recent developments into context. With- 
out stretching the definition of remote sensing 
excessively, it is suggested that virtually all 
the techniques now in use involve remote sen- 
sing. The major exceptions are the trapping or 
netting methods where individuals are con- 
tacted, constrained, banded, tagged, or other- 
wise marked and released. The second nonre- 
mote technique for population census involves 
the use of age, sex, and kill data. In this 
method also, the manager has the beast or bird 
in hand and can determine specific facts about 
it as well as having positive knowledge that it 
existed in the population. 
What of other census techniques? Track 
counts are frequently used to determine popu- 
lation trends and habitat use by animals. They 
represent a form of sensing remote from the 
animal in time. Track counts are indefinite: 
one is never sure whether one or many animals 
were involved in making a specific grouping of 
tracks. Likewise, when conditions are not 
right, no tracks are visible. 
Like track counts, pellet group counts are re- 
mote in time from the animal and usually can- 
not be referred to a specific animal or time. 
Populations on large areas can be sampled ef- 
fectively with pellet group counts. The tech- 
nique has been highly refined, both in the Mid- 
west and the Far West. It is primarily suitable 
for large herbivores that deposit a conspicuous 
and persistent pellet group, particularly when 
feeding on woody plants. At first, the pellet 
group count was not considered suitable for 
summer estimations of populations. However, 
McCaffery, Creed, and Thompson (1967) of the 
Wisconsin Department of Natural Resources 
demonstrated that pellet counting is an effec- 
tive census for research purposes during the 
spring, summer, and autumn. Deterioration of 
pellet groups in the summer is much more 
rapid, so frequent counts must be made. 
By combining a refined pellet group count 
for the white-tailed deer with knowledge of 
herd dynamics from age, sex, and kill data, 
Michigan and Wisconsin scientists have been 
able to obtain reasonably accurate population 
figures on which intensive management is now 
based. 
Drives, one of the first management and cen- 
sus techniques used, are also a form of remote 
sensing. A crew of ‘‘beaters’” moves through an 
area, causing animals to move so that they may 
i cecal 
