112 MASSACHUSETTS HORTICULTURAL SOCIETY. 



In this case the determination can have sufficient value only when one has 

 many pieces to study. 



This work of determination is very long, and will demand of me still 

 much time ; on the other hand, the results to which I have arrived need to 

 be presented under a form comparative, synoptical, and easily available. 

 To this end I have drawn up a uniform table for all the species of birds ; 

 each copy of this table concerns a species whose name figures at the head. 

 It represents a series of columns, of which each bears the title of an 

 alimentary regimen ; it is in these columns, and conformably to their title, 

 that I have inscribed both the date of the observation and the indication of 

 the objects found in the stomach. In fine, each of these tables contains a 

 sufficient number of lines to register observations made during twelve 

 months in the year, and at five different dates in each month. 



Behold, at a glance, some of the preserved specimens and some of the 

 tables ; many others are in my hands, and bear indications more or less 

 complete, but of which, the collection, as I have formed it, possesses data 

 without the time necessary to make it complete. 



I will terminate this memoir with the indication of some general results 

 concerning the questions which I have suggested at the commencement of 

 it. The studies which I have pursued after the method indicated above 

 will establish the fact, that the same species of bird changes its food 

 according to the age and season of the year. One will see by the series of 

 stomachs preserved that the most part of the granivorous species are 

 insectivorous in their immature age, and become such anew during adult 

 age at each period of reproduction ; an analogous fact is observed even in 

 the species which, in the spring and the commencement of summer, devour 

 buds and young leaves. Some birds of prey, truly carnivorous, also mingle 

 insects in their food according to circumstances. It has appeared to> me, 

 upon the whole, that insects occupy in the food of birds a considerable 

 part. This singular privilege can be attributed to the prodigious multi- 

 plicity of the latter, as well as to the analogy of their locomotion with that 

 of birds. It is, in effect, at the moment when certain insects inundate a 

 country with individuals without number, that, coetaneously, this very 

 abundance seems to invite a crowd of different species of animals to feed 

 upon them. 



The common Hanneton (May bug) and some kindred species offers to us 

 an example of this kind. When these insects appear in perfect condition 

 we soon find their remains in the stomach of the greater part of the birds 

 which inhabit our country at that epoch, and even in the stomach of more 

 than one mammifer, from the humble field-mouse to the wolf, so habitually 

 carnivorous. 



In order to avoid entertaining you with hypothetical ideas, I will not 

 speak here of the opinions which I have myself cherished in respect to the 

 causes of these actions, although I am constantly preoccupied in investi- 

 gating them. But one of their consequences merits notice. I am in course 

 of proving that birds are in general much more useful than injurious to our 

 crops, and that even in respect to the greatest part of the granivorous 



