One day fifteen years ago I was sitting on a low bank near Baronett's Bridge across the Yellowstone, a mile and a half from Yancey's. The bank was in an open place, remote from cliffs or thick woods; it was high, dry, and dotted with holes of rather larger than field-mouse size, which were further peculiar in that most of them went straight down and none was connected with any visible overland runways.
All of which is secondary to the fact that I was led to the bank by a peculiar bleating noise like the "weak" of a Calling Hare, but higher pitched.
As I passed the place the squeakers were left behind me, and so at last I traced the noise to some creature underground. But what it was I could not see or determine. I knew only from the size of the hole it must be as small as a Mouse.
Not far away from this I drew some tracks I found in the dust, and later when I showed the drawing, and told the story to a naturalist friend, he said: "I had the same experience in that country once, and was puzzled until I found out by keeping a captive that the creature in the bank was a Grasshopper Mouse or a Calling Mouse, and those in your drawing are its tracks."
At one time it was considered an extremely rare animal, but now, having discovered its range, we know it to be quite abundant. In northern New Mexico I found one species so common in the corn-field that I could catch two or three every night with a few mousetraps. But it is scarce on the Yellowstone, and all my attempts to trap it were frustrated by the much more abundant Deer-mice, which sprang the bait and sacrificed themselves, every time I tried for the Squeaker.
In the fall of 1912 I was staying at Standing Rock Agency in North Dakota. On the broken ground, between the river and the high level prairie, I noted a ridge with holes exactly like those I had seen on the Yellowstone. A faint squeak underground gave additional and corroborative evidence. So I set a trap and next night had a specimen of the Squeaker as well as a couple of the omnipresent Deer-mice.
Doubtless the Calling Mouse has an interesting and peculiar life history, but little is known of it except that it dwells on the dry plains, is a caller by habit;—through not around the campfire—it feeds largely on grasshoppers, and is in mortal terror of ants.