the ease with which misleading conclusions 
may be drawn from samples limited to a single 
season or year. If differences over time are to 
be evaluated and understood, sampling must 
continue for reasonably long periods. 
Seasonal diets are usually reported accord- 
ing to some arbitrary division of the calendar. 
Winter (January-March), spring (April- 
June), summer (July-September), and autumn 
(October-December), or similar compartmen- 
tal arrangements are often used. Some refine- 
ment in definition of diet periods to orient 
them more closely with seasonal changes in 
both the foods and their consumers would be 
profitable. It is important to know the develop- 
mental stage of a food item at the time of con- 
sumption. Also, the physiological state of ani- 
mals undergoes periodic changes during an an- 
nual period. These periodic changes could in- 
fluence dietary selection. 
During certain times of the year, or in some 
years compared to others, animals may un- 
dergo periods of stress. Diets may be modified 
during these critical periods. Access to foods 
may be difficult or may change with changing 
environmental conditions. Periods of drought 
(Errington 1937; Korschgen 1958), flood 
(Loveless 1959), deep snow and low tempera- 
tures (DeNio 1938; Harris 1945; Hill 1946; 
Leach 1956; Morris and Schwartz 1957), high 
population pressure (Scheffer 1951; Hosley 
1956; Jensen 1958); food failure (Goodrum 
and Reid 1962), and fluctuating rainfall 
(Baumgartner et al. 1952; Napier 1963; Ander- 
son et al. 1965) modify the kinds and amounts 
of food available to the consuming animal. Ad- 
ditional and expanded studies are needed to 
sample animal diets during critical periods. 
Why is it Consumed? 
Animals select from available foods. Some 
foods are more palatable and are preferred 
over others that may be available in equal 
quantity. Answering the why of food consump- 
tion is much more difficult and complex than 
answering the what, where, and when. The 
subject has an extensive literature and has 
been reviewed by Heady (1964). He listed 
five factors influencing relative food prefer- 
ence: (1) Palatability, (2) associated species, 
(3) climate, soil, topography, (4) kind of ani- 
mal, and (5) animal physiology. Heady’s state- 
ment summarizing Cowlinshaw and Alder 
(1960) appears particularly applicable. 
“The act of selecting food is undoubt- 
edly influenced by all four [groups of 
factors] and can only be finally un- 
derstood in terms of interactions 
among them. Unfortunately, most 
studies to date have concentrated on 
single factors, or even more simply, 
just recording the magnitude of pref- 
erence.” 
Why certain foods are more palatable than 
others is also poorly understood. Studies ori- 
ented toward explaining variability in food 
palatability and in animal preference offer 
many research opportunities.’ 
What are the Relationships? 
The influences on animal diet are apparently 
many, complex, and interrelated. Emphasis 
must be placed on ecological relationships if di- 
etary data are to have the most meaning. Eval- 
uation of the effects of variable and changing 
environmental conditions is essential. The in- 
fluence of climate and weather, fluctuating 
food availability, seasonal and annual changes, 
animal competition, population pressures, envi- 
ronmental manipulation, and factors influenc- 
ing choice or selection among food items by an- 
imals of different sex, age, and condition must 
be recognized and interpreted. The associations 
between dietary consumption, food quality, and 
animal physiology have only begun to be un- 
derstood. Greater depth of interpretation and a 
more critical examination of relationships can 
improve the value of a technique that has had 
both historic and current application. 
*Longhurst, W. M., Oh, H. K., Jones, M. B., and 
Kepner, R. E. A basis for the palatability of deer for- 
age plants, Thirty-third N. Amer. Wildlife and Natu. 
Res. Conf. Trans. 1968. (in press). 
LITERATURE CITED 
Adams, Lowell. 
1957. A way to analyze herbivore food habits by 
fecal examination. Twenty-second N. Amer. 
Wildlife Conf. Trans. 1957: 152-159. 
O’Reagan, W. G., and Dunaway, D. J. 
1962. Analysis of forage consumption by fecal ex- 
amination. J. Wildlife Manage. 26: 108-111. 
Ahlen, I. 
1965. Studies on the red deer, Cervus elaphus L., in 
Seandinavia. III. Ecological investigations. 
Viltrevy 3: 177-376. 
140 
Alkon, P. U. 
1961. Nutritional and acceptability values of hard- 
wood slash as winter deer browse. J. Wild- 
life Manage. 25: 77-81. 
Anderson, Allen E., Snyder, Walter A., and Brown, 
George W. 
1965. Stomach content analyses related to condition 
in mule deer, Guadalupe Mountains, N. Mex. 
J. Wildlife Manage. 29: 352-366. 
Arata, Andrew A. 
1959. A quick method for gross analysis of muskrat 
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