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IOWA ACADEMY OP SCIENCE 
destruction of the pocket gopher. If this family of hawks is a fair example, 
I think it safe to estimate the number of pocket gophers caught by a family of 
red-tailed hawks during a summer at one hundred. Aside from pocket gophers 
the food consisted of prairie grey squirrels, striped ground squirrels, rats and 
field mice. During the entire time that the birds were under observation, they 
were only observed to have two small chickens about the size of quail. In 
making my first report of this observation, (Forest and Stream, Vol. 74, No. 25), 
before the work was quite concluded, I reported only one chicken. The second 
was observed after the article was written. As an example of the bill of fare, 
they were seen to have three pocket gophers, a prairie grey squirrel and two 
field mice in one day. On no occasion did I see any evidence of reptiles or 
batrachian. 
Of Cooper hawk, Fisher says; “Cooper hawk is preeminently a chicken 
hawk, and is by far the most destructive species we have to contend with. 
* * * * It is especially fond of domesticated doves. * * * * 
real and ground squirrels appear to be the mammals most frequently taken by 
Cooper hawk.” 
I found it even more difficult to ascertain the nature of the food taken by 
this family, than the red-tails, but my observation is almost exactly in line 
with Dr. Fisher’s conclusions from the stomach examinations. During the 
first weeks of observation I found no evidence of any food excepting poultry, 
pigeons and birds. Seldom did more than two days elapse between chickens, 
and frequently, chickens were taken for several days in succession. When 
the hay was cut about the middle of July, a change was at once apparent in 
the food brought to the nest. A large part of the food now consisted of ground 
squirrels (spermophiles), though they still continued to revert to chicken 
quite frequently. No trace of tree squirrels or other mammals was found. 
Referring again to Fisher, concerning the Sparrow hawk, he says: “It is 
the only one of the true falcons which can be placed in the mainly beneficial 
class. At times it attacks birds and young chickens, but these irregularities 
are so infrequent that they are more than outweighed by its good services 
by destroying insects and mice. Grasshoppers, crickets, and other insects form 
the principle food during the warm months, while mice predominate’ during 
the rest of the year.” 
The Sparrow hawk, being more confident, was easy to observe; in fact, a 
pair very obligingly took up their abode in a box erected in the front yard and 
reared their family there. The birds would permit me to approach within a 
short distance, and I could see the mice they carried about, long before the 
young appeared in the nest. The nest was examined frequently for fragments 
in order to get as full information as possible. While grasshoppers and crickets 
formed a considerable portion of the food, mice apparently predominated during 
the entire time. A few striped ground squirrels were taken and an occasional 
small bird. The feet of the birds were sent to Washington for identification 
and were found to be for the most part English sparrows, though a few black 
throated buntings and song sparrows were included. Though the hens with 
their fiocks of young chicks were unconfined, never did I know of them taking 
one, though I think I would have known had they done so, as we kept careful 
