THE EDINBURGH JOURNAL OF NATURAL HISTORY, 



preference to some one kind of insect food during summer, but be obliged 

 to resort to another sort in winter. Again, times of scarcity, even of 

 staple supplies, to the feathered creation will occur, when, if the diges- 

 tive powers and instinctive faculties of birds were of very limited operation, 

 their races, so far as the dearth extended, must become exterminated. 

 Very many kinds emigrate to other climes, and so escape these contin- 

 gencies of our country; other species continue to feed on insects the 

 year through, and by superior diligence, aided by a probable diminution 

 of appetite, they manage to survive the rigours of our winters. Thus, 

 the Gold-crest subsists exclusively on insects, in summer feeding on a 

 variety of these, and in winter seemingly, at least with us, confining itself 

 to minute coleoptera collected from the bark of trees, especially apple- 

 trees. The Creeper, also, does not vary the nature of its food, but in 

 winter searches out these same beetles and aurelia?, while in summer, 

 the abundance of insect food of all kinds renders this extreme diligence 

 superfluous. But with other birds the case is different. Certain of the 

 smaller species which regale during summer on fruits and insects, must 

 limit themselves much to the latter in the ungenial months ; for example, 

 the Blue Tit, Robin, and Blackbird. The Tit-lark feeds in summer on 

 caterpillars and beetles, but in winter' its subsistence must be precarious. 

 Perhaps the Winter- Gnat forms great part of its food, as it does of several 

 other birds, being indeed a most wonderful demonstration of care and 

 provision for many kinds in the severe part of that season of want. The 

 Linnet and Greenfinch also, which are principally granivorous, must, I 

 apprehend, betake themselves to insect food in the depth of winter. The 

 Rook is a bird which gives the preference to insect food, that is to say, 

 worms and grubs, but when we are afflicted, as is often our. lot, with a 

 long-continued summer-drought, these birds will carry off potatoes newly 

 planted, and in subsequent periods of want will do great damage to newly- 

 sown corn land. Now, if birds could not, on the subsidence of their sum- 

 mer diet, or on the occurrence of emergencies, find resources in other 

 food, and betake themselves to supplies different from their accustomed 

 provender, they must inevitably perish. 



With respect to the organization and forms of birds, as indicative of 

 their food, but few results can be arrived at on that point from these 

 sources. Let us first examine the bill. A hooked bill does not exclu- 

 sively belong to rapacious birds, and some rapacious kinds have it not. 

 Moreover, the association of a hooked bill and membranaceous stomach 

 will not indicate a bird of prey, certainly not an exclusive feeder on live 

 quarry, birds, quadrupeds, reptiles, or fish ; for the Kestrel at times cap- 

 tures beetles, and the Shrikes subsist largely on those and other insects. 

 By the same instances we see that a combination of a hooked bill, thin 

 stomach, and strong curved claws, is likewise insufficient to indicate a 

 predatory bird. A notched bill will not assist in discriminating a bird 

 accustomed to tear flesh, for this structure descends from the Shrikes, 

 which are partially carnivorous, to the Thrushes and Flycatchers, which 

 are not so. The large, strong, sharp-edged bill of the Pies will not 

 indicate an omnivorous appetite, for the Ox-eye is omnivorous, and 

 has a short and very conical bill. The knobbed bill of the Bunting will 

 not point out exclusive granivorous habits, nor will the strong conical 

 bills of the Finches. These and the Larks subsist on seeds and insects, 

 and yet how different are their bills ! I question if there be an instance 

 of an exclusively granivorous bird. 



Let us now see how far the structure of stomachs characterizes the 

 diet of birds. Membranaceous stomachs appear in the Accipitres ; but 

 they are also seen in the omnivorous species of Parus, in the Cormorants, 

 and other birds. The stomach of the Pinnatipedes are nearly membrana- 

 ceous. Thick muscular stomachs appear in the Finches, Gallinae, some 

 of the Palmipedes, the Land Rail, the Bearded Titmouse, and in a vast 

 number of other birds. Thin muscular stomachs occur in the Pies, 

 Gralta, some of the Palmipedes, and others. 



There are not a few birds which will betake themselves voraciously to 

 two or more kinds of food, eating together with their more ordinary pro- 

 vender what one might imagine would constitute their reserve ; a suspi- 

 cion here naturally arising that their constitutions need this admixture at 

 certain seasons. Thus, the Common Bunting will, at the height of sum- 

 mer, partake both of green corn and beetles. Thus also the Thrush, 

 Blackbird, and Robin, will combine fruits and insects. Again, the Greater 

 Tit or Ox-eye is an instance of an omnivorous appetite ; he is a general 

 consumer, one who can accommodate his palate to every dish set before 

 him; he will swallow seeds, corn, snails, various insects, offal meat, and 

 will also at times kill small birds, and feed on their bodies. The Flusher 

 is not so indiscriminate a feeder as the Ox-eye, but yet it will devour 

 small birds and insects. Birds whose strength of bill indicates their adap- 

 tation for eating seeds, or hard food, will partake largely also of insects. 

 Thus, the Sparrow, Chaffinch, Reed Bunting, and Common Bunting, ge- 

 nerally spoken of and ranked as "granivorous birds," yet eat largely of 

 beetles and other insects. Those birds generally considered "insecti- 

 vorous," having a soft flexible bill, are in numerous cases likewise fruit 

 eaters. The Robin, for instance, the Fauvette, the Blackcap, and the 



Willow Wrens, though these last will never touch cherries, the trne ob- 

 ject of their visits to cherry trees being to procure the small insects found 

 in abundance on them at the time of the ripening of the fruit. " Insecti- 

 vorous" birds, however, are seldom granivorous, for whilst, on the one 

 hand, the granivorous kind can, by extensive powers of comminution and 

 digestion, easily assimilate food of a softer description, the insectivorous 

 having usually stomachs suited only to soft and readily digestible food, , 

 cannot, it would seem, mollify and digest the hard structure of seeds. 

 Yet this matter is not altogether cleared up, for the Ox-eye has an 

 membranaceous stomach, and occasionally will swallow hard seeds 

 and corn, to say nothing of garden peas, of which he devours large quan-' 

 tities, in which respect he resembles the "granivorous" birds. Perhaps 

 the gastric juice in this species may have stronger solvent powers 

 than usual, and the digestive powers of birds possessing similarly con- 

 structed stomachs vary greatly, as we have already exemplified above in 

 "insectivorous" birds, part of which live exclusively on insects, while 

 others eat fruit in addition. Sky Larks, which have gizzards, feed on 

 grain, seeds of various kinds, other vegetable substances, and insects. 

 The Nuthatch eats insects, particularly beetles, and kernels of nuts. By 

 all which instances of unexpected combinations of dissimilar food, whether 

 eaten at one and the same time, as is frequently the case, or partaken of 

 in rotation, as is the habit of some species ; and by the few instances, out 

 of a very extensive list, given before, to show that the same kind of 

 stomach occurs in birds dissimilar in general characters, and is not con- 

 stant to all the species of one tribe in certain cases ; it appears that some 

 other less equivocal structure or agent than the bill or stomach, one hav- 

 ing more decided and constant characters, must be sought for to explain 

 facts of such anomalous natures. 



Here, however, we judge rather by results, for the gastric juice, which 

 I here allude to, gives but slight opportunities for investigation. Still I 

 this liquid must vary even with the species, as appears by statements 

 above made, and it must alter in quality also, I presume, in some cases, 

 according to the alteration in diet adopted by the birds ; and more than 

 this, it must differ in different individuals of one species at the same pe- 

 riod, for a reason already explained. It seems, indeed, quite subservient 

 to the immediate requirements of the bird. It is rational to conclude 

 that the gastric juice is of a more active quality in membranous stomachs, 

 and less in gizzards ; but then we should recollect that flesh is more 

 readily digested than other aliment, that caterpillars and other soft mat- 

 ters are consumed by birds with gizzards, and that the thickness of the 

 walls of stomachs has no direct power in digesting, but only in comminut- 

 ing. We certainly are quite incapable of explaining why this or that 

 bird has a gizzard, and another not. The facts are frequently adverse to 

 our preconceptions and theoretic calculations. The Bearded Tit lives 

 on seeds, beetles, snails, and flies ; but who would have concluded that 

 it had a gizzard, and that provided with gravel ? The young of many 

 birds, whose powers of digestion and comminution are immature, feed 

 differently from the parents. Sky Larks feed their young with worms, 

 ants' eggs, grasshoppers, and caterpillars ; so also do the Robin, Green- 

 finch, and Chaffinch ( To be continued.} 



eoje's classification of birds. 

 In the Isis for 1826 is an arrangement of birds- in outline, which, al- 

 though possessing considerable merit, seems to have been almost entirely 

 overlooked, until recently brought into notice by its having been referred 

 to by the Prince of Musignano in his Comparative List of the Birds of 

 Europe and North America. The number of primary sections or orders 



is five Raptores, Insessores, Rasores, Grallatores, Natatores. 



Order I. Raptokes, Vigors. 

 Fam. I. Gypogeranidre, Vigors. 



Gypogeranus, Illig. — Serpentarius, Cuv — Falco serpentarius, Linn. 



Dicholophus, Illig D. cristatus, Illig. col. 237. 



Fam. II. Vulturida?, Leach — Vultur, Linn. 



Vultur, Linn. — V. cinereus, Linn. — V. angolensis, Lath. 



Cathartes, Illig Neophron, Savigny. — Catharista, Vieill — Mona- 



chus, Temm. 



Sarcorhamphus, Dumeril V. Gryphus, Linn — V. Papa, Linn. 



Fam. III. Falconidse, Leach. 



Polyborus, Vieill F. brasiliensis, Gmel. 



Gypaetus, Storr Phene, Savigny — Falco barbatu?, Gm. 



Haliaetus, Savigny Falco leucocephalus, Gm. — F. Macei, Cuv. 



Aquila, Bechst F. armiger, Shaw. 



Pandion, Savig F. Haliaetus, Linn. 



Circaetus, Vieill F. Gallicus, Gm. 



Buteo, Bechst F. Tachardus, Shaw. 



Pernis, Cuv. — F. apivorus, Gin. 



Astur, Bechst Daedalion, Savig F. columbarius, Gm. 



Morphnus, Cuv. — F. Guianensis, Daud. 



Harpyia, Cuv F. cristatus, Gm. 



