| Sex | Date of capture and marking as pouch young | Date of recapture | Distance in feet |
|---|---|---|---|
| Female | April 14, 1951 | September 22, 1951 | 1870 |
| Female | May 6, 1950 | February 28, 1952 | 1800 |
| Female | May 14, 1950 | December 31, 1950 | 1750 |
| Female | March 28, 1951 | January 23, 1952 | 1700 |
| Female | May 11, 1951 | November 9, 1951 | 1700 |
| Female | May 11, 1951 | March 2, 1952 | 1450 |
| Female | April 2, 1950 | October 7, 1950 | 1160 |
| Female | April 14, 1951 | May 19, 1952 | 1100 |
| Male | May 11, 1951 | February 3, 1952 | 800 |
| Female | May 11, 1951 | January 9, 1952 | 700 |
| Female | April 2, 1950 | October 3, 1950 | 700 |
| Female | May 6, 1950 | April 3, 1951 | 650 |
| Female | March 28, 1951 | February 2, 1952 | 500 |
| Male | April 18, 1952 | July 6, 1952 | 120 |
| Female | April 2, 1950 | April 14, 1951 | 10 |
Most of these opossums were recaptured within a year of the time they were marked as small young in the females' pouches, and on the average they had moved a little less than 400 yards. While the sex ratio was equal in the pouch young that were marked, it is noteworthy that all but two of the recaptured opossums were females; and of the two males, one was recaptured early, before it could have had time to wander far. The young males, after becoming independent must tend to wander much more widely, and to settle in new areas far removed from the mother's home range. It is unlikely that this dispersal of the young males is motivated either by rivalry and intolerance of larger males or by sexual drive. The dispersal occurs in late summer when there is no breeding activity, and when food is present in greatest abundance and variety.
The feeding habits of the opossum in Douglas County, northeastern Kansas, have been discussed by Sandidge (1953). His data were obtained from stomach analysis of specimens caught in steel traps. In the present study no stomachs were available for analysis as the opossums on the Reservation were not sacrificed for this purpose and effort was made to avoid mortality in those that were live-trapped. Information concerning their feeding habits was obtained mainly by examination of scats in the field. On this 590-acre tract maintained as a Natural Area with human disturbance kept to a minimum, the available food sources differed somewhat from those of other woodland areas and especially from those of cultivated or suburban areas as reported upon by Sandidge.
The feces or "scats" of the opossum are not liable to be confused with those of other mammals except possibly with those of the striped skunk or raccoon, both relatively uncommon on the Reservation. Favorite sites for deposition of opossum scats were at the bases of large trees, usually honey locusts or elms, near the animal's den. Accumulations of several dozen scats may collect in such situations. Often the opossums live-trapped were found to have deposited scats and many of these were saved for examination, although they were usually trampled, broken and mixed with earth and hair. Few scats were seen in the field throughout the summer. Their disintegration is rapid at that time of year because of the high temperature, frequent heavy rains, and abundance of dung-feeding insects. Scats were seen in greatest abundance in the fall, partly because the opossum population was then at its annual high point. During fall, wild fruits made up the greater part of the diet and were represented in almost every scat that was seen. Wild grape (Vitis vulpina) is an abundant woodland vine on the area and often forms dense tangles both in deep woods and in edge situations. Grape was the most abundant single item, and a large number of scats consisted exclusively of grape seeds and skins. In November and December opossums could be trapped most effectively by making sets in or near grapevine tangles where the animals were attracted by the abundant ripe fruits. The crops of wild grapes were especially heavy in 1948 (before live-trapping was begun) and in 1949, and scats containing them were noticed in those years especially. Opossums, too, were more numerous on the Reservation in 1948 and 1949 than they were in 1950, 1951, and 1952.
Hackberry fruit (Celtis occidentalis) was second to grape in importance and large numbers of scats were found to be composed mainly or entirely of the skins and seeds of this fruit. In the fall of 1951, these fruits were especially important and were the principal food source.
Wild plum (Prunus americanus) and wild crabapple (Pyrus ioensis) also are important in fall and winter and are present in many scats. In summer, blackberry, abundant on some parts of the Reservation, is an important food. Other wild fruits noticed in scats include those of cherry (Prunus virginiana) and climbing bittersweet (Celastrus scandens), and mast (acorn ?). In the fall of 1948, corn made up a large part of the contents of scats noticed. Crops of corn were grown on two fields of the Reservation in that year. In following years, corn was noticed less frequently in scats but still continued to be one of the important food items. Several cornfields adjoined the Reservation, and the scats containing the grain were observed mainly along the borders of these fields.
The crayfish is evidently the most important animal food, at least during the cooler half of the year when scats are seen in greatest numbers. Remains of crayfish were far more conspicuous than those of other invertebrates, and often made up the greater part of the scat. The sample of scats examined in the field, as noted below, are thought to be representative of the much larger number noticed but not examined in detail.
August 19, 1951, 16 scats. Food items in their approximate order of importance were: blackberry in six (100% in 5, 95% in 1); grape in five (100% in 2, 97% in 1, 95% in 1, 50% in 1); crayfish in three (100% in 1, 60% in 1, 40% in 1); wild plum in two (85% in 1, 5% in 1); wild crabapple in two (100% in both); insects in three (scarabaeid beetle 10% in 1, cicada 2% in 1, unidentified insect fragments in 5); fox squirrel in one (15%); unidentified plant fibers in one (40%).
September, 1951, 16 scats. Grape in seven (all or most of 5 scats and small percentages of 2 others); cherry in seven (all or most of 5 scats and small percentages of 2 others); crayfish in seven (all or most of 5 and small percentages [Pg 323] of 2 others); rabbit in two, making up most of both; insects (grasshopper, and large black beetle) in two making up small percentages.