138 TRANSACTIONS OF THE ILLINOIS 



Consequently little can be alleged to the discredit of this bird, 

 while the figures given speak strongly in its praise. It apparently well 

 deserves what little protection and encouragement we can give it during 

 its brief stay. It breeds far to the north (rare summer stragglers occur- 

 ring in Northern Illinois, according to Mr. E. W. Wilson), and probably 

 winters wholly beyond our limits. By Dr. Cones this is regarded merely 

 as a variety of Swainson's thrush. 



swainson's thrush {Turdus Swainsoni, Cab.) 



Swainson's thrush is another migrant, of which I have too few speci- 

 mens for generalization. I have carefully studied six specimens, one 

 taken in April and five in May. These indicate a general resemblance 

 to the food of its near ally (the Alice thrush, just mentioned), but 

 present differences which I give for what they are worth. 



There were no mollusks in these stomachs, but many crane-flies 

 (twenty-two per cent.), very many ants (twenty-eight per cent.), too 

 many Harpalidse (five per cent.), several curculios, and in one stomach 

 a mass of short-horned borers, Scolytus muticus, Say. 



A glance at a single stomach shot in Kentucky, in August, showed 

 that this bird, probably like all the other migrants of this family, takes 

 wild grapes at least on its return trip from the north. 



General Discussion and Summary. — We now come to the last and 

 most interesting step of this investigation in its present form, to a com- 

 parison of the different species with each other, and a summary of results 

 for the family as a whole. To this end, I have prepared two tables — one 

 elaborate, giving for each species the totals of the food in all its details, 

 and another brief and compact, presenting the totals only of the most 

 important elements, in which the species have been found to vary most. 

 The full discussion of the former table would inordinately lengthen 

 this paper, and would have little value at present, and I will confine 

 myself to the latter. 



We note at once the fact that there are few differences in the kinds 

 of food taken by the different species of this family, the occurrence of 

 fragments of grain in the stomachs of the brown thrushes being almost 

 the only notable exception in this respect. When we examine the per- 

 centages, however, we find peculiarities so numerous and definite that 

 we are able easily to construct a series of specific descriptions of the food 

 almost as well marked as the descriptions of the species themselves. I 

 have also prepared, more as a curiosity than anything else, an analytical 

 table of the species, based upon the food characters, from which I find, 

 on trial, that I can determine the species of any group of half-a-dozen 

 bottles now in our collection. Some of these differences will, probably, 

 disappear (many of them, perhaps) when more specimens are studied 

 (a kind of experience not unknown even to those who describe species); 

 but these tables serve to exhibit, at a glance, the present state of the 

 research. 



Running down the column given to the robin, we find but a trace of 

 mollusks, few ants, many caterpillars, crane-flies and predaceous beetles. 



