98 THE RAPTORIAL BIRDS OF IOWA 



state, individuals with practically no clear white, but with rusty wash- 

 ing on the under parts and with rufous barring on the tibial flags are 

 to be found; and a specimen of calurus taken in Johnson county, 

 though of much lighter shade, has a more characteristically barred 

 tail than a very dark specimen of calurus from California. 



Specimens are at hand which at a glance present the characteristics 

 of the eastern variety, but careful examination of the tail feathers 

 (especially near the shafts of the lateral ones) will reveal traces of 

 dark bars in addition to the subterminal one. Few specimens, how- 

 ever, which suggest at first sight the western variety, are without evi- 

 dent traces of more than the subterminal bar. Iowa seems to be a 

 "melting pot" for the species and its varieties. 



In the spring of 1915 a female bird in immature plumage was re- 

 ceived from Allamakee county. This specimen is interesting when 

 considered in conjunction with a hawk of the same species killed by 

 the writer in July, 1902, at Clear lake, which was changing from im- 

 mature to adult plumage. In this specimen most of the tail feathers 

 are of the barred immature type, while some are of the red adult 

 coloration with black subterminal band. One adult red feather is 

 grown to only half its full length. It would seem that the Red-tailed 

 Hawk does not pass into the adult plumage until the summer follow- 

 ing the year in which the bird is hatched. 



Albino Red-tailed Hawks are occasionally secured. 



Typical Eastern Red-tailed Hawks do not appear to be common in 

 eastern Iowa. Few specimens with white unmarked tibial flags and 

 under tail coverts have been found. Intergradation with the western 

 form is common, and birds are not easily placed under any restricted 

 description. The varieties of this species range from Alaska to the 

 islands beyond Florida and from New Foundland to eastern Mexico. 

 Iowa is so located that these varieties, with the exception of the 

 Alaskan form, come within its borders. There are in the Coe Col- 

 lege Museum skins of the Eastern Red-tail and of its three varieties 

 (viz., krideri, calurus, and harlani) all collected in Linn county. 



