40 TRANSACTIONS OF THE ILLINOIS 



tainty and continuity. Serious mistakes are easy, and indeed unavoid- 

 able, and a distorted notion of the food of the bird will necessarily arise 

 in most cases, since it will be seen so much more frequently in some situ- 

 ations than in others. The contents of the stomach, however, furnish a 

 record of the food usually during several hours' wandering — a kind of an 

 old bill of fare — often difficult to decipher, with occasionally a name 

 obliterated, and yet, on the whole, comprising material for a very com- 

 plete diary. Of these three methods, the last is undoubtedly much to be 

 preferred. A combination of the three, if the results are treated judi- 

 ciously, would probably be more trustworthy than either alone. 



I have depended, during the past summer, entirely upon the exam- 

 ination of stomachs. The stomach and crop — if it had one — of every 

 bird shot at the Museum, during the spring and summer, were put imme- 

 diately into fresh alcohol when the bird was skinned, with a number 

 attached, referring to a list. This list gave the name of the species, the 

 date when shot, the locality and the exact situation, whether field, marsh, 

 orchard, garden, etc. About 350 stomachs were thus obtained from Nor- 

 mal and its vicinity. Arrangements were further made with Messrs. E. 

 W. Nelson, of Chicago, and Fred. T. Jenckes, of Providence — two orni- 

 thologists, who proposed to spend the collecting season in the field in 

 Northern Illinois — to prepare, in a similar manner, the stomachs of all 

 the birds shot by them. Consequently, at the end of the season, I found 

 that I had over 1,000 stomachs on hand, in excellent condition, repre- 

 senting the birds of McLean and Cook counties during the spring and 

 early summer, and the former during the latter part of the summer and 

 early autumn also. 



At this point, I might perhaps have properly concluded that the 

 labors of the ornithologist were finished for the year, and that the matter 

 should now be turned over to the specialists in botany and entomology ; 

 but I was unwilling to come before you without some contribution to a 

 knowledge of the subject in which you are especially interested ; and I 

 have therefore examined, more or less thoroughly, the contents of 220 of 

 these stomachs, and have brought the results together in the form of a 

 table, constructed to show, in as small a space as possible, the facts already 

 alluded to as the essential ones for our purpose. The contents of these 

 stomachs have all been placed in separate vials, and these vials numbered 

 to correspond to the list mentioned above, so that my conclusions can be 

 at any time tested by reference to the original data. I need not say that 

 I have not exhausted the subject. Probably there is not a specimen here 

 that could not be made to yield from five to ten times as many facts as I 

 have so far got out of it. I have made no more than a preliminary exam- 

 ination, and the results given must be regarded as subject to revision, and 

 capable of much greater elaboration. Lack of time, and the fragment- 

 ary nature of the material, ground sometimes to a powder of microscopic 

 fineness, together with the difficulty of the subject, have forced me to con- 

 tent myself, at least for the present, with few specific names. But in most 

 cases I have been able to bring the identification within limits sufficiently 

 narrow for our purpose. 



