THE CKOW AND ITS RELATION TO MAN. 69 
wild fruits, as sumac, poison ivy, poison oak, bayberry, dogwood, 
sour gum, cherry, and juniper, ceases when the soft outer portion has 
been utilized. To aid even in this process of digestion crows swallow 
large quantities of sand, gravel, shell fragments, or anything else 
that will serve as a grinding medium. After a large number of such 
seeds have been eaten and the digestible portions assimilated, the 
remains are regurgitated. The fact that embryos of these seeds are 
seldom affected by this process, and that a large part of those dis- 
gorged are capable of germination, brings up the important problem 
of seed distribution. 
The material so disgorged usually assumes an ellipsoid or spheri- 
cal form, but is quite variable in size (PI. II, fig. 1). These masses, 
commonly called pellets, as in the case of similar ejecta of birds of 
prey, are found in great abundance at crow roosts, and wherever a 
place has been occupied by these birds for several successive winters 
a substantial growth of their common food plants usually springs up. 
An idea of the number of seeds deposited at one of these roosts 
may be gained from the following description given by Prof. 
Barrows : 1 
The following facts serve to show how extensive is this seed planting by- 
crows in the vicinity of the winter roosts: On February 8, 1889, I visited the 
well-known — almost historical — crow roost located on the Virginia side of the 
Potomac River just opposite Washington, D. C. The exact location of this roost 
varies from time to time, but at the date mentioned it was entirely within the 
grounds of the National Cemetery at Arlington, and covered an area of 12 or 15 
acres of second-growth deciduous trees. The ground beneath these trees was 
pretty evenly covered with the ejecta of the crows, forming a deposit which in 
places was an inch or more thick, though the average deposit was probably 
rather less than half an inch. A representative spot free from underbrush was 
selected, and all the material above the leaves from an area 2 feet square was 
carefully collected, dried, and examined. The weight of this material when dry 
was almost exactly 1 pound, and it contained (aside from gravel, bits of bone, 
shell, corn hulls, and some excrement) the following seeds: 
Poison ivy (Rhus toxicodendron) 1,041 
Poison sumac (Rhus venenata) 341 
Other sumacs (Rhus) 3,271 
Juniper or red cedar (Juniperus virginiana) 95 
Flowering dogwood (Corrius florida) 10 
Sour gum (Nyssa sylvatica) 6 
Total 4, 764 
A little calculation shows that the roost of 15 acres must have contained 
upward of 778,000,000 seeds, or more than enough to plant 1,150 acres as 
thickly as wheat is sown. . 
A series of nine pellets, gathered at a former roost near St. Louis, 
Mo., and examined by the writer, contained an average of 36 poison- 
1 Barrows, W. B., The Common Crow of the United States : Bull. 6, Div. of Ornith. and 
Mamm., U. S. Dept. Agr., pp. 23-24, 1895. 
