Stomach Content Analyses: Collections from Wild Herbivores and Birds 
DEAN FE. MEDIN? 
Estimating dietary consumption of wild her- 
bivores and birds by examining material found 
in their digestive tracts has been a technique 
applied by professionals for more than a cen- 
tury. In 1858, Jenks analyzed the contents of 
robin stomachs in Massachusetts, and he has 
been considered the American pioneer in the 
method. Beal, Cottam, Forbes, McAtee, Judd, 
Barrows, Lantz, Kalmbach, Wetmore, Gabriel- 
son, Merriam, and Sperry in the United States 
and Prevost, Schleh, Rorig, Herman, Gilmour, 
and Collinge in Europe were prominent early 
workers (Kalmbach 1934; Martin et al. 1951). 
During the pioneering period, interest lay 
primarily in determining the economic status of 
bird species and in giving popular recognition, 
understanding, and protection to birds. These 
objectives were apparently well attained (Dav- 
ison and Hamor 1960). Leopold (1933), Kalm- 
bach (1934), and Errington (1935a) expressed 
the need for further and expanded observation 
and experimentation, not only with birds, but 
with other animal groups, particularly with 
those animals involved in the rapidly develop- 
ing field of wildlife management. 
McLean (1928), Dixon (1928 and 1934), 
Forbes and Bechdel (1931), and Hosley and 
Ziebarth (1935) undertook early studies of die- 
tary consumption in deer. Dixon’s work in Cal- 
ifornia remains a classic study in the use of ob- 
servational methods to estimate animal diets. 
Forbes and Bechdel may have been first in 
publishing results of stomach examinations in 
wild ruminants. Errington (1932) and Dalke 
(1935) reported new techniques of studying 
raptor and upland game bird food habits. 
Foods eaten by predaceous mammals began to 
receive attention about the same time (Erring- 
ton 1935b; Murie 1935). 
From these beginnings have come greatly ex- 
panded and more refined approximations of an- 
imal diet. Analysis of stomach contents, or 
contents of other divisions of the digestive 
tract, has continued to be a useful technique 
for these approximations. 
SOME USEFUL REFERENCES 
Errington (1932 and 1935a), Cowan (1945), 
Kalmbach (1954), Julander (1958), Talbot 
(1962), and Gullion (1966) are a few who 
have pointed out the significance, application, 
and continuing need for dietary research. 
‘The author is a Range Scientist and is stationed 
at Boise, Idaho. His project is under the jurisdiction of 
the Intermountain Forest and Range Experiment Sta- 
tion, USDA, Forest Service, Ogden, Utah. 
Recent studies applying digestive tract anal- 
ysis methods include those of Dirschl (1963), 
Boag (1963), Talbot and Talbot (1963), Ward 
(1964), Bishop and Hungerford (1965), An- 
derson et al. (1965), Pulliainen (1965), Rogers 
and Korschgen (1966), Kolev (1966), Bear and 
Hansen (1966), Irving et al. (1967), Scotter 
(1967), and Bradley (1968). 
Specialized study objectives, anatomical and 
trophic differences between animal groups, 
various limitations not subject to investigator 
control, and the constant search for new and 
improved methods have stimulated application 
of techniques other than analyses of digestive 
tract contents. Some have been used indepen- 
dently; others have been used as supplemental 
or correlative approaches. 
Adams (1957), Hungerford (1957), Hercus 
(1960), Hegg (1961), Storr (1961), Adams et 
al. (1962), Lay (1965), Korschgen (1966), 
Kiley (1966), and Stewart (1967) examined 
fecal material. 
Observation of browsing or utilization has 
been carried out in various forms (Julander 
1937 and 1958, Deen 1938, DeNio 1938, Das- 
mann 1949, Smith 1952, Smith and Julander 
1953, Smith 1954, Webb 1959, Crouch 1966, 
and Severson and May 1967). 
McLean (1928), Dixon (1934), Hahn 
(1945), Buechner (1950), Saunders (1955), 
Cole (1956), Harry (1957), Wilkins (1957), 
Lovaas (1958), Knowlton (1960), White 
(1961), Harper (1962), Lamprey (1963), Dav- 
ison and Sullivan (1963), Ahlen (1965), Dzie- 
ciolowski (1967a), and Harper et al. (1967) 
observed free-ranging wild animals or exam- 
ined feeding sites following feeding activity. 
Free-ranging tame or semitame animals were 
observed at close range by Buechner (1950), 
Wallmo (1951), Dunkeson (1955), Brown 
(1961), McMahan (1964), and Dzieciolowski 
(1967b). 
Confined animals have been used in estimat- 
ing food requirements and forage preferences. 
Forbes and Bechdel (1931), Maynard et al. 
(1935), Davenport (1937), Nichol (1938), 
Smith (1950), Smith and Hubbard (1954), 
Dahlberg and Guettinger (1956), Alkon 
(1961), Brown (1961), and Duvendeck (1962) 
have successfully used confinements to obtain 
such estimates for deer. Useful data from cap- 
tive animals have been obtained by Nestler et 
al. (1945), Jensen and Korschgen (1947), Ar- 
nold (1942), and Currie and Goodwin (1966) 
with jackrabbits, Michael and Beckwith 
(1955) with bobwhite quail, McFarland and 
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