THE EDINBURGH 



JOURNAL OF NATUEAL HISTORY, 



AND OF 



THE PHYSICAL SCIENCES. 



FEBRUARY, 1839. 



ZOOLOGY. 



ON THE FOOD OF BIRDS. BY J. C. BELLAMY, ESQ. 



In Nature we everywhere discover a system of gradation. If we look 

 upon objects generally, we observe a gradation of forms ; and if we com- 

 pare their parts, we find a gradation in the constitution of their organs. 

 Since also there are relations and dependences established between vari- 

 ous parts and organs of living beings, for the execution of more or less 

 complex actions, and since these organs and apparatus are but the instru- 

 ments of the actions of living bodies, a gradation is further discoverable 

 in these also, whether of an internal or external nature. 



The natural world has been so arranged, that the different beings hold 

 various connections and relations of a complex character. We see but 

 little of objects being accomplished by single agencies : a number of agents 

 usually conspiring to effect a purpose ; and though there may be one 

 chief agent, others act subordinately in concert. We see the effect pro- 

 duced by causes acting on a system of gradation, that is to say, by causes 

 which are less and less active and conspicuous, so far as that one object 

 is concerned, but which, in the production of other objects, play a more 

 decided and active part. In this way, the perfection of coustruction of 

 the organs, apparatus, and parts employed to effect a given purpose, as 

 observed in the principal agents, and their less and less perfection, and 

 the gradual disappearance of the structure in the minor agents, is ex- 

 plained, in so far as an elucidation can be given of the primary laws of 

 Nature. 



Since the ordinations and intentions of Nature are effected by beings 

 differing widely in general points of view, though certainly for the most 

 part by beings of congenerous characters, the folly of endeavouring to 

 trace out the links of a presumed chain of gradation in a simple, linear 

 manner, from Man to the lowest form of vegetation, and the impropriety 

 of framing a classification or arrangement of natural objects on this sup- 

 posititious principle, need not be pointed out. The day also for classify- 

 ing objects in Nature according to the structure of one organ or apparatus, 

 is now, I believe, past. The discovery of the system on which Nature 

 herself has planned the series of beings will supersede the necessity of 

 inventing generalizations of this kind, and will, of course, demonstrate 

 more forcibly than ever the suspicion at various times promulgated by 

 another set of systematists who advocated the propriety of classifying 

 natural objects by their aggregate conformation, that the organ or part, 

 or particular formation of a part, apt to be selected as the standard for 

 classifying a certain series of beings, often exhibits so many gradations, 

 and passes so frequently into objects every way, except in this, totally, 

 different in character, and probably themselves already classified and 

 systematically arranged by another standard, that this method of classi- 

 fying brought together subjects perfectly incongruous and heterogeneous. 

 In the case of Birds, any attempt to arrange them according as they 

 are eaters of flesh, or grain, or fruits, or herbs, would, besides bringing 

 together species of very different structures and habits, induce a belief in 

 students that their appetites were in all instances limited, as implied in 

 the name of the class under which they might rank ; whereas not only 

 would the species so ranked possess opposite or varying tendencies in 

 respect of appetite, but also in many cases an individual species would 

 1 



exhibit altered habits and appetite according to the season of the year ; 

 and finally, individuals belonging to one species would be seen at one and 

 the same time to affect different localities, and to feed differently. The 

 names of garnivorous, insectivorous, carnivorous, &c, should be used 

 merely as ordinary words, and by no means be employed as technicalities. 

 In Temminck's classification of Birds, we have the orders Insectivora, 

 Granivorce, and Omnivorce, so named, I presume, par excellence, for else 

 the epithets are highly contradictory. Indeed, as it is, their impropriety 

 is quite manifest from very many instances. Thus Parus occurs in Gra- 

 nivorce, Turdus in Insectivora ; not to mention very many other cases 

 where the genera might as properly have been placed in one division as 

 the other, or even in Omnivorce. Dichotomous methods and classifica- 

 tions, which assume a particular organ or structure, as the standard of 

 comparison, may be admissible on small scales, and are surely highly con- 

 venient, but a different method must be adopted in disposing of the 

 whole series of beings, and in the determination of physiological points, 

 our deductions are not to be overruled by existing ordinal or other names. 

 Systematists have been unfortunate in searching for order and method in 

 the wrong quarters ; where the imagined order was to be found, there 

 Nature displays the greatest tendency to vary ; the order of Nature is dis- 

 coverable in general results, in the completion of general objects and 

 plans, and in the unity and harmony of the principles on which she seems 

 to have planned the series of beings. 



The bills of birds are manifestly chiefly employed to collect, and in 

 part to comminute their food. A gradation of the various shapes and pe- 

 culiarities they assume is well known to exist. The stomachs of birds 

 are exclusively used for the digestion and preparation of the food col- 

 lected, and in these also a gradation of structure, and various peculiarities 

 exist, though not so extensive or appreciable. But both organs are sub- 

 servient or secondary to the general character, organization, and habits 

 of the respective possessors, and are accordingly unfit to be the ground- 

 work of a classification of this tribe, even on this one account, not taking 

 into consideration the weightier reasons before named. 



But besides that it is improper to class birds under denominations in- 

 dicative of exclusive habits of feeding so contradictory to truth, or to found 

 a system on the varying structure of one particular organ, the bill or 

 stomach for instance, individual birds are known to differ in habits from 

 the rest of their kind, from local circumstances, or some occult peculiari- 

 ties of situation, their instincts directing them, as it were, to avail them- 

 selves of their extended powers of digestion. 



It is extremely important for all who are commencing the study of 

 Nature to attach little or no importance to names. Thus, "insectivorous," 

 " carnivorous," and "granivorous" birds they will in many cases find to 

 vary their food. It will be found, however, on inquiry into the structure 

 and digestive powers of their stomachs, that the food they partake of is 

 in all cases agreeable to their organizations, and that their capacities of 

 appropriation are ever adequate to the comminution and digestion of the 

 food selected. If we reflect, also, for a moment, it must appear that often 

 the number of resources must be enlarged, or the lives of birds sacrificed. 

 Those, for instance, which live for the most part on fruits and seeds 

 during summer, must have other resources during winter ; and there are 

 numerous instances where generally the individuals of a species will give 



