296 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. i. 



One of the traps set at this nest was carried off by a rascally 

 Prairie Wolf, presumably with a wood rat in it. About a week 

 later, in a ravine a mile further west, I found an immense fallen, 

 hollow cottonwood tree, literally packed full of sticks, etc. 

 Pulling and punching at this mass, the young man who was with 

 me finally ran* a large rat out, which quickly disappeared in a 

 hollow limb of the same tree, but not before I could see it was 

 of a bluish gray color. Having no axe with me, I was compelled 

 to give up the chase, but returned the next day and set some 

 Schuyler Rat Killers in and about the trees. On looking around 

 after setting these traps, I found about 100 yards lower down the 

 ' draw ' a nest of this rat, or another one. Out of the hollow 

 tree where I first found the rat, the male was taken in a trap set 

 at the front entrance to the nest. Not more than 30 feet from 

 this nest stood a large partially decayed cottonwood, full of 

 holes, and this tree I am positive held more of the rats, as well 

 worn runways led from it to this nest and the bark was much 

 worn on the side of the tree from the animals climbing up it, 

 but although I kept traps set continually around and near the 

 tree and nest until my departure several days later, I got no 

 more Neotomas. I took a photograph of this nest and 

 measured it accurately. It was built under the spreading 

 branches and within a few feet of the base of a large cottonwood 

 tree and was five feet in diameter by two feet in height. Though 

 composed mainly of sticks, some of large size, and leaves, there 

 was a large amount of other material in it, such as many pieces 

 of prickly pear cactus and heads of the sumach, sand burrs, 

 horse, cow and coyote manure, etc. Being very compactly 

 built, I should imagine if would cause considerable exertion on 

 the part of a coyote or badger to tear it open. There were three 

 entrances to the nest near the ground, one near the base of the 

 tree and the other two showing in the photograph. Each 

 entrance was about five inches in diameter, but slightly broader 

 than high. The nest was against the base of the ravine's wall 

 among the grass, and sprouts of some species of ' gum-bark ' 

 bush, the sprouts showing perfectly white where they had been 

 denuded of their bark by the rats. From the nest several 

 smoothly worn runways extended in as many directions, some 

 going up the ravine through the tall, rank grass which forms a 

 roof to the runway quite up to the fallen tree where the male was 

 taken, a distance of fully one hundred yards. Another runway 

 leads up the back of the ravine to the level prairie above. This 



