Trippe.] 232 [October 16, 
ever, some difference in the number of individuals of the same spe- 
cies. 
The nomenclature is from Baird’s P. R. R. Report. 
1. Cathartes aura. Abundant; breeds. Arrives early in April 
or late in March, and remains till late in October, or even November. 
2. Falco anatum. Isawa pair of hawksin April, in Decatur 
County, which I took to be this species, though possibly they were 
not. I had a good view of them, however, and could hardly have 
been mistaken. 
3. Falco columbarius. Seen a few times in Mahaska County, 
in fall only. 
4. Falco sparverius. Abundant; breeds. Next in abundance 
to the Marsh Hawk. It arrives in the middle of March, and stays till 
the middle of autumn. During the latter part of summer, when the 
young have become strong on the wing, I have frequently seen scores 
of these birds sitting on the telegraph wires at distances of fifty or a 
hundred feet apart for half a mile or more. 
5. Accipiter fuscus. Seen quite often in fall, but never during 
the breeding season. This hawk follows and preys upon the flocks 
of wild pigeons that visit the country chiefly in early spring and fall. 
I have shot it in the act of devouring a full-grown pigeon, which it 
had just caught and killed. 
6. Buteo borealis. Common; breeds; resident. Seen chiefly 
about the timber. 
7. Archibuteo sancti-johannis. Common from the middle 
of November to the middle of March. Prefers the timber, but is fre- 
quently seen far out on the prairies. 
8. Nauclerus furcatus. Not very common; breeds. Seen 
only in Decatur County. Arrives early in April; leaves in late sum- . 
mer. 
9. Circus Hudsonicus. Abundant; many breed. Arrives late 
in February, and remains till winter. 
10. Halieetus leucocephalus. Seen only in winter, and then 
infrequently. 
11. Pandion carolinensis. Seen once in spring, in Decatur 
County. 
12. Bubo eee Not common. Seen but a few times, 
in winter only. 
13. Otus wilsonianus. Seeu a few times in fall only. 
