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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
bulkier products (2). Today, muskrats are fairly common along 
the Raccoon river and the Boyer, also along some of the smaller 
creeks and About Wall lake and the “Goosepbnd. ” In the winter 
of 1915-16, after the “Goosepond” was full of water all sum- 
mer, a local trapper stated that over two thousand muskrats 
were trapped. 
Meadow Mouse (Micro his pennsylvanicus) . These were com- 
mon in early days (4). Today, they are found in every slough 
or field where there is a rank growth of vegetation. In the win- 
ter they often infest stacks of clover hay and do much damage. 
They do not frequent corn fields, except sometimes in winter, 
and where there is a rank growth about the edges. 
Prairie White-footed Mouse (Persy sens maniculatus bairdi). 
This mouse is very common in corn fields at alb times of the 
year. .It is also found in stubble fields, but to a lesser extent. 
While disking a fall-plowed clover stubble in the spring, I have 
disked these mice out of the ground in the center of a thirty 
acre field. I also saAv a Franklin gull capture and swallow entire, 
one of these mice, when I was disking the same field. 
Brown or Norway Rat (Mas decumanus) . The first barn rat 
came in a box of goods from New York state in the spring of 
1858. It escaped and was trapped the next fall in Cory’s 
groA 7 e (4). Brown rats were next reported in 1868 (2) and 
1870 (3). 
House Mouse (Mas musclus ) . I obtained no first data for the 
house mouse, but they were here in 1870 (8). 
Beaver (Castor canadensis). Beaver were very common. The 
darns they built across the Raccoon river were so numerous 
(about one-half mile apart) that there was slack water nearly 
all the way up the river (1, 3, 4), “My partner and I caught 
the last beavep, thirteen of them, on the ‘Coon’ river straight 
east of Lake View in 1870 (4). This was the last dam built 
on the Raccoon river (4). The last beaver on the Boyer river 
were seven which were trapped in 1886 by Mr. Levey, to the 
west of Wall Lake (7, 8). One man trapped six beaver in seven 
nights with one trap (1). The beaver steadily decreased from 
the time of the first settlers (4). One pioneer said that a man 
on the Maple river in Ida county protected beaver and that 
there were always beaver there (3). I know a local trapper 
who reported beaver along this river in 1904. 
