BJKUS OF INDIANA. 783 



"I think they remain mated for life, as I have not only noted. cer- 

 tain peculiarities of the birds occupying the same nesting site from 

 year to year, but have been able to identify certain pairs by some pe- 

 culiar shape or markings of the eggs. 



"Toward the latter part of March they are at work repairing the old 

 home, or, if it has been destroyed, in building a new one in the same 

 locality, and by the first of April the females commence laying. The 

 earliest date that I have taken the eggs of this species was March 29, 

 1890, when I took a set of two fresh eggs near Waterloo. This set is 

 remarkable for several reasons. In the first place, at the time I took 

 it, the weather was very cold, the ground was covered with snow, and 

 the lower part of the nest was a solid mass of ice, the only dry and 

 warm spot being the cavity, about eight inches in diameter, which 

 had been covered by the bird. The eggs are also unusually large, 

 measuring 1.98 by 2.50 and 1.99 by 2.49 inches. This set is now in 

 the collection of Mr. H. W. Flint, of New Haven, Conn. 



"From April 1st to the 15th, fresh eggs may be found, but after 

 that date they are too far advanced in incubation for preservation. 



"My observations would indicate that the period of incubation cov- 

 ered about 18 days. 



"Out of about 25 sets of eggs I have taken the stages of incubation 

 average as follows: Fresh, April 5; slightly incubated, April 8; incu- 

 bation advanced one-half, April 12; nearly ready to hatch, April 17; 

 young just hatched, April 21. 



"On March 10, 1891, while after Great Horned Owls' eggs, near 

 Waterloo, I saw a Red -tail fly from a large nest, and shot her. After 

 ascending the tree and finding the nest completed, but no eggs, I 

 opened the bird (female) and found a very large and completely 

 formed egg, with a hard shell, and evidently about ready to lay. This 

 would have been a record breaker, as it was nearly twenty days earlier 

 than I ever found their eggs. 



"The nests are large, made of sticks, lined with small twigs, leaves, 

 and sometimes grass, and usually placed in the fork of a large tree 

 beech, oak or ash anywhere from 35 to 100 feet from the ground. 



"The birds generally leave the nest upon the approach of any one 

 and remain at a good distance, circling about and uttering a peculiar 

 "squeal" very unlike the harsh scream of the Bed-shouldered Hawk. 



"The usual number of eggs in the sets I have ta,ken is two, and 

 never have I found more than three. The largest set was taken April 

 13, 1890, a few miles from Waterloo, in Dekalb County, and is now 

 in the State Museum at Indianapolis. My record book contains tlio 

 following record of this set: 



